I love growing crystals. It’s a great family activity, and a very cool science experiment. You can make beautiful ones from sugar, alum, or even table salt.
But one of the easiest and most beautiful crystal you can grow is actually a common fertilizer. It’s called monoammonium phosphate (MAP) and it gives plants the nitrogen and phosphorus they need.
MAP is cheap, non-toxic and under the right conditions, grows into stunning crystal clusters. In fact, it’s the ingredient inside most crystal growing kits. More surprisingly, these crystals are also grown industrially and have military and space applications (more on that later).
There are many guides on growing crystals online, but none of them go into great detail and they don’t show you just how stunning these crystals can be.
I’ve been growing crystals for 3 years now, and I’ve learnt a few tricks to get great crystals.
Some crystals I grew on a small branch overnight. Later, I’ll show you how I made it.
In this article, I’ll cover the best crystals I’ve grown, share the exact procedure I used, and show you beautiful specimens grown by other hobbyists.
Growing crystals at home
The idea is simple. Dissolve the MAP powder in water until it is saturated. Wait for seed crystals to form, and harvest them after a day. Transfer the seed crystals to a bigger container and let them grow.
I’ll go through each step with you.
Materials
For growing crystals, you’ll need:
- A packet of MAP fertilizer
- A pot to dissolve the powder
- A jar to grow the crystals in
- A filter funnel/coffee filter
- Some thread/fishing line
- A small dish
- A spoon
- A pencil
You can find monoammonium phosphate (MAP) in gardening stores as a fine white powder. Sometimes, it’s also called ammonium dihydrogen phosphate (ADP). If you can’t find it, you can order some online.
How much MAP you need depends on how big you want to grow the crystal. 500g is enough to grow a crystal the size of your palm. Theoretically, there is no limit to how big you can grow them, provided you have enough solution and a sufficiently large container.
A massive 6.5-pound crystal grown by Terry Bartlett, a long time crystal growing enthusiast.
Some insanely impressive MAP crystals by Spanish artist Isabel Lopez.
This guide will be split into 6 sections:
- Preparing the solution
- Growing seed crystals
- Growing big crystal clusters
- Growing perfect single crystals
- Growing crystals on objects
- Troubleshooting & FAQ
All the steps are very easy to follow.
Preparing the solution
Technically, MAP is a type of salt. Like table salt, it dissolves in water. At room temperature, 100 mL of water can dissolve about 40 g of MAP. Hot water can dissolve more.
Let’s start. First, prepare some hot water. For every 100 mL of water, dissolve 60 g of MAP. Stir until all the powder dissolves. I’m using a beaker, but you don’t have to.
Filter the solution into a jar using a coffee filter to get rid of dust and impurities. Then, leave the solution to cool down.
Growing seed crystals
Once cool, our solution is ready. Now, we want to start growing small crystals to act as “seeds” that will form bigger ones in the future.
First, sprinkle a pinch of MAP powder into the solution, and stir it vigorously. After about 30 seconds, you should see a lot of extra crystalline dust forming. This is exactly what we want.
The dust is actually made of thousands of microscopic crystals that formed when you disturbed the supersaturated solution.
Then, leave the jar alone for 1-2 hours.
When you come back, you’ll find that the dust has formed crystals! Also, there might be some small crystals floating on the surface of the solution.
Great.
Give them some time to grow.
The next day, the crystals should look like this:
Pour the leftover solution into another container. After that, remove the chunk of crystals at the bottom of the jar. If it’s stuck, put the jar face down and knock hard to make it come loose. It’s no big deal if the chunk breaks apart.
Now that you have an assortment of small seed crystals, it’s time to grow bigger ones!
Growing big crystal clusters
Don’t discard the leftover solution. It’s perfect for this step.
But what if you don’t have enough solution left?
Easy. Make more.
But this time, we’re making a growing solution. This solution should be less concentrated than the solution we used to grow seed crystals. Growing crystals from this solution makes them clearer and higher in quality.
So, you want to dissolve 45 g of MAP per 100 mL of water. Like before, stir until all the powder dissolves.
At this point, I’d also like to teach you how to control the shape of the crystals. By default, MAP forms thick prismatic crystals. When you make the solution more acidic, the crystals resemble sharp, pointy spikes.
This seed crystal was grown from a more acidic solution. As a result, the spikes are longer and sharper.
A very easy way to increase the acidity is to add alum, used in baking and water purification. It can be found at the grocery store, or bought online.
Depending on how spiky you want your crystals, add anywhere between 0 and 1 gram of alum per 100 mL water.
Dissolve the alum in the MAP solution. Like before, filter the solution and wait for it to cool.
Then, pour the solution into a dish, and gently place a seed crystal in the middle. Since you have so many seed crystals, you might want to do a few of these at once.
This will be your growing setup. Leave it in a sheltered area, somewhere that isn’t directly exposed to the wind or fan.
Depending on your conditions, the seed crystals will start growing within a few hours, and be noticeably bigger within a day. After 3 days, this is what the crystal in the picture above looks like:
Isn’t it amazing, how you can just grow crystals at home?
To give you an idea of how adding alum affects the shape of the crystals, here are some pictures of MAP crystals I grew using the same setup.
Crystals grown with (0, 0.25, 0.5, 0.75, 1 & 1.25) g alum / 100 mL water over 3-6 days.
1 and 2 are quite lumpy, with few distinct crystals. Their number and length greatly increase as more alum is added.
After a few days, your crystals should be decently sized. Select the most beautiful ones, and transfer them to a bigger container filled with the same growing solution (45 g MAP / 100 mL water) and the desired amount of alum.
Place the crystal inside, and wait for it to grow big!
Smaller crystals like to form at the side. They compete with your main crystal for growth, but don’t bother removing them. Attempting to do so only causing crystal dust to form and stick everywhere.
Instead, either a) blow them away with a dropper or b) pour the solution to a new container and move the main crystal there.
Observe how lots of smaller crystals like to form alongside the main crystal. There’s a clear ring in the middle because I blew them away with a dropper.
Once you’re satisfied with their size, you can harvest and dry them on a paper towel. Don’t wash them though, because they will slowly dissolve in water.
Here’s my crystal after 3 weeks:
A star shaped crystal grown with more alum over the course of 3 weeks:
An even spikier one, taking just 1 week to grow:
Super cool.
Note that the more alum is added, the faster the crystals appear to grow. Actually they grow at the same rate; sharper spikes grow longer faster, but individually they contain less crystal mass.
Growing crystals at the bottom of the container means they will always be flat on the underside. If you want to grow more symmetrical clusters, you can hang the seed crystals using a thin nylon fishing line.
The crystals are quite hardy, and it’s safe to handle them. But the crystals on very spiky specimens are sharp and much more fragile – so be careful.
If you’re a parent, watch as your kid falls in love with science. If you’re a kid, show them off, and you’ll automatically become the coolest kid in class.
But wait! There’s more to it.
Growing perfect single crystals
So far, we’ve been growing crystals in the form of clusters.
MAP can also form single crystals that look like gems. Growing them will require a different approach.
Here’s a video I made. You can watch it, or continue reading the article below.
Prepare another growing solution. Pour it into a dish. You don’t need to add any powder or seed crystals. Just leave it in a sheltered place for a day or two.
You should notice some clear, individual crystals start to form.
As they get bigger, they will start to grow into each other, which is bad.
So, we want to isolate the crystals by hanging them with a fishing line. Pick them out with a pair of tweezers and tie them onto the line. Tie the other end to a stick.
And here are the results:
Like before, adding alum will make the crystals spikier. Check out this super sharp needle, grown from a solution with 1 g alum / 100 mL water.
Perfectly balanced, as all things should be.
And this beautiful star, consisting a pair of single crystals grown into each other.
They even have a baby.
You might have noticed that these crystals have imperfections on their surface. You can reduce these flaws by growing them under more stable conditions, but the main issue is because the MAP fertilizer isn’t pure.
To get pure MAP, you need to buy lab or reagent grade monoammonium phosphate, which is more expensive. Then the crystals will have perfectly flat edges.
Some very pure MAP crystals I grew.
In fact, we’re not the only ones growing crystals.
MAP crystals are grown industrially to be used in electronics and optics. They also have piezoelectric properties, which means that they accumulate electric charge when hit. It was even the subject of a 1963-1965 crystal research project by DARPA, and massive single crystals of pure MAP are grown by the National Ignition Facility to be used in lasers.
Here’s a picture of one of those crystals from the DARPA project, provided by Reddit user u/tlbmds who obtained it from an estate sale. His post contains more information.
Growing crystals on objects
In this section, we’ll be growing crystals on objects.
First, select something that you want to crystallize. Ideally, it should be rough, and have some bigger features. Stuff like rocks, branches and sculptures. Don’t choose delicate objects with fine features like dandelions. Those features will not be preserved.
Now, prepare 2 solutions, one big and one small, with concentrations 50 g and 60 g MAP / 100 mL water respectively.
Stir, filter and wait for it to cool.
Two solutions. Food coloring has been added to the bigger batch.
Sprinkle some MAP powder into the smaller jar. Stir vigorously to form the crystalline dust. Then, immediately poke your object into the jar to let some of the dust stick on it. Let it stay there for about 30 seconds.
Then, remove it from the small jar, and immerse it into the big jar – and you’re done.
The crystal dust should start forming crystals on the object. Within a few hours, my branch looked like this:
The next day:
Get creative with this process. Here are some ideas:
- Try solutions of different concentrations.
- Try crystallizing smooth surfaces.
- Try gluing the seed crystals on the object.
- Try not using seed crystals
- Try immersing the object in stages.
- Try growing crystals from a solution without alum, then place them in a solution with alum. And vice versa. This one is very interesting. What do you observe?
Here are some beautiful specimens from the crystal growing community.
Ice blue crystals on red pine bark by artist Stefan Herda. You can see more of his creations on his website.
A crystallized cicada by Adrienne DeLoe, who specializes in preserving insects through art.
Another gorgeous cluster of orange crystals by Isabel Lopez.
Troubleshooting & FAQ
There are a few places where things might go wrong. All of them are easy fixes. They also apply to crystal growing kits that you buy at the store.
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Why are crystals not forming?
Try dropping a pinch of MAP powder into the solution and see if crystals form. Sometimes they need something to kick start their growth. Otherwise, it’s possible that your solution is not concentrated enough. Either reheat the solution and add more MAP, or pour it into a flat dish to speed up evaporation.
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Why did my crystals dissolve?
This occurs when you put an existing crystal into an undersaturated solution (same problem as above). I recommend preparing large batches of solution at once, so that you don’t have to keep worrying about this issue.
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Why are my crystals not transparent?
The crystals grew too quickly. The supposedly perfect crystal lattice structure contains lots of defects as a result. Your solution was likely too saturated. Reduce the concentration of the growing solution from 45 to 40 g MAP / 100 mL water, or even lower (if you live in a cold climate).
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Why do my crystals look like an ugly clump?
Same problem as above. Also, make sure the solution does not become too low until it exposes the crystal to the air. Stop growing or add more solution before this happens.
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What is this weird crust creeping up my container?
Air movement causes crystals to form above the surface, on the walls of the container. It then sucks up more solution, growing upwards. This effect seems to increase with the addition of more alum.
Aside from slowing down evaporation, there’s nothing much you can do about it. Just pour the solution into another container and continue growing. Besides, once you stop freaking out and take a closer look, they’re kinda beautiful.
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Why are crystals not sticking to the object?
Your solution is not supersaturated enough. If the 60 g MAP / 100 mL nucleation solution doesn’t work, go for 70 g. If it still doesn’t work, the surface of your object is probably too smooth.
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What is the recommended amount of alum to add?
It depends on your taste. But use less alum (< 0.25 g alum / 100 mL water) if you want super clear single crystals, and use more alum (> 0.5 g alum / 100 mL water) if you want well defined crystal clusters. Doing the opposite will encourage the growth of jagged single crystals and formless white clumps respectively.
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Why did white stuff form after adding alum?
Your water / MAP fertilizer likely contains impurities. One of the uses of alum is to remove impurities from water by precipitating them out. It’s annoying, but nothing to worry about. Filter it away, and continue growing crystals.
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What is the issue with food coloring?
It’s tricky to dye the crystals. The food coloring you use might react with the solution in unexpected ways. My purple food coloring turned blue in the solution. I can’t give much advice here, because every brand of food coloring is different. I’ve heard of people using vegetable carbon, cochineal, even highlighter ink. Feel free to experiment, and remember to stay safe.
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Can I make jewelry with these crystals?
No. The crystals are too brittle and cannot be polished. They have a Mohs hardness of around 3. They also dissolve in water. You wouldn’t want a water soluble gem to be a symbol of everlasting love, do you?
Nail polish gives an additional layer of protection. Some people have suggested sealing it in epoxy resin. I haven’t tried it before, but it might work. Let me know if it does.
Being naturally air stable, they do make for good decorations.
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What other crystals can I grow?
After growing crystals for years, I’m constantly amazed by this hobby. I recommend trying out alum (yes, alum by itself can grow into stunning octahedrons).
***
That’s all for this guide. If you enjoyed it, share it with your friends. If you have any questions, feel free to leave a comment below.
And if you’d like to see crystal growing videos, you can check out my new YouTube channel.
Happy growing 🙂
The only mono ammonium phosphate I can find is in fertiliser with limestone and calcium nitrate, will that make a big difference?
How much monoammonium phosphate is included together with the limestone and calcium nitrate?
If the fertilizer mainly contains MAP, then it’s still okay to grow crystals with it.
Do it matter if its in glass, plastic or silicone containers??
Nope, it’s fine with any container.
Thank you .
How do you discard the solutions you don’t want anymore
You can just pour monoammonium phosphate solution down the drain – it is a type of fertilizer, and nontoxic.
Though I recommend just keeping the solution in a jar, you can always use it to grow more crystals in the future. They don’t expire.
Hi Chase,
Cool Crystals! Do you think your method would work on these toy hedgehogs on Amazon?
https://www.amazon.com/Hedgehog-Toy-Figurines-Decoration-Cognitive/dp/B0C2J88J57/ref=sxin_25_sbv_search_btf?content-id=amzn1.sym.5cde1a09-4942-4242-87c5-e66d2d3b6a3c%3Aamzn1.sym.5cde1a09-4942-4242-87c5-e66d2d3b6a3c&crid=3DYSWOS7W13IT&cv_ct_cx=hedgehog+plastic+toy&dib=eyJ2IjoiMSJ9.2DTkqFEqDWky685sKH3y4g.QnP8Qgt93JeQR6_y8Mzl6d7WTl56QHQqVdtl4R3I9pM&dib_tag=se&keywords=hedgehog+plastic+toy&pd_rd_i=B0C2J88J57&pd_rd_r=68c54f35-f8bd-4c9b-ab7e-9f947c24261e&pd_rd_w=poKLs&pd_rd_wg=jT6V7&pf_rd_p=5cde1a09-4942-4242-87c5-e66d2d3b6a3c&pf_rd_r=W8CJH71MRHN5ZVY7EHPH&qid=1718740551&sbo=RZvfv%2F%2FHxDF%2BO5021pAnSA%3D%3D&sprefix=hedgehog+plastic+toy%2Caps%2C208&sr=1-1-5190daf0-67e3-427c-bea6-c72c1df98776
I am teaching science to a kids day camp and I’ve seen expensive kits for hedgehog crystal growing kits and I thought it would be cool to DIY it to a plastic toy. If I just dip the spiky ends into the powder and prop it in the solution, do you think it would form crystals? Thanks for your advice!
Hey there. Those are cute 🙂
Yes, it will work. You’ll need to use the supersaturated solution (60g/100mL), using the method that I used to grow them on branches.
Some of the dust should stick to the hedgehog. If it still doesn’t stick, then try dipping the plastic into the saturated solution quickly, then let it dry. A fine powdery crust will form on the plastic. Then, re-immerse it into solution to let the crystals form on the crust.
Hello!
Looking for advice. Every time I make a solution and add my main growing crystal to it, there is a lot of tiny crystal particulate forming on the bottom and very little main growth. Is there a way to mitigate this?
Thanks for the help!
Add 5 mL of plain water, and reheat the solution until everything dissolves.
Wait for it to cool, and then place a single seed crystal carefully into the new solution. It should start growing normally.
“Don’t discard the leftover solution”: What do I do with it? Does it need more MAP to be saturated first, or can I just ad crystals and they’ll start growing?
You can add seed crystals immediately and start growing.
Alternatively, you can also store the leftover solution in a sealed container – and keep it as long as you like. After say, 1 year, if you feel like growing crystals again, you can drop a seed inside, and resume the growing process right away.
Does the leftover solution need topping up with any more MAP of you’ve already used it grow crystals or is it good to go for another round?
Good to go for another round straight away
Hi Chase,
Thanks so much for sharing all your findings and for this amazingly informative guide – left you a tip 🙂
I’m a ceramic artist, exploring something called the “clay hypothesis” in my new series of works – it’s the idea that biological life first evolved by using microscopic quartz crystals as a kind of scaffolding.
Would you have any tips for growing these crystals on a ceramic vase?
My guess is that where the piece is glazed (and very smooth) less nucleation would occur, so perhaps remain crystal free. So I could perhaps leave some parts heavily textured and unglazed to promote crystal growth?
Any hints you might have on controlling what parts of a ceramic vessel I could grow crystals on would be very welcome!
Thanks Fred!
There’s a trick to growing crystals on smooth surfaces. First prepare a really saturated solution (about 60g MAP/100 mL hot water), and spray a thin layer on the ceramic surface while it’s still hot. If you want to prevent crystals from growing on certain parts of the vessel, simply cover those parts with masking tape when you’re doing the spraying.
On those sprayed regions, a white, crusty crystal layer will form in just a few minutes. They sometimes look like frost patterns on glass. Now, immerse this coated ceramic surface in a proper growing solution, and larger crystals will start to grow over the next few days.
Good luck 🙂
Btw is there a website or social media page where I can see your work? I’d love to check it out!
Awesome, thanks Chase. Would have taken me ages to figure this out! Will give it a go.
Best place to see my works is my insta page – @fredgwatkin
I mostly make vessels using a 3D clay printer and did a whole series inspired by botryoidal malachite. Will be cool to incorporate actual crystals into my work, so appreciate all the tips.
Seems like MAP growth can be quite similar to quartz crystals under the right conditions and that’s exactly what I’m going for.
Hey! I’m unable to find alum locally and it’s taking too long for delivery. Is there anything I can use as a replacement?
What about aluminum sulfate? Maybe you can give it a try
Hi!
Do I have to use alum while making the crystal?
No, alum only makes the crystals more spiky.
Hey,
I want to give crystal growing a try, but as far as I did my research, MAP is not that common of a product in my country. Would MCP fertilizer be a good substitute? Not very experienced in this field 😅
Hey Luka! MCP doesn’t work. The ones that work are (MAP aka ADP – which is the one I suggested) and (MKP aka KDP, which gives equally good results).
thank you for this article- I can’t wait to try this!
Please add me to your newsletter.
Alright, will do. Happy growing 🙂
I’ve tested and see that rainwater is a replacement for alum. this must be due to the acidic rain. Although if use as a alum replacement, you need to be careful or else the rainwater may solute the crystal( in case of saturated solution)
That’s a great find! I’m not sure if other acids work (phosphoric acid doesn’t seem to work). But rainwater is certainly the most convenient. Thanks for sharing.
But it depends heavily on where you live like if you live in such a good place , the rain wouldnt be acidic enough and you dont know its pH unless you test it with litmus paper or something.
Hi. I’ve been trying to coat my MAP crystals to protect them. I’ve used lacquer sprays, but there an reaction to the crystal. A few crusts form. I’ve read to use acrylic. I thought because it’s water based, it would affect the crystal? Also how important is it too rinse the crystal properly. If it dries with traces on MAP on it still, will this also cause a reaction when applying the coating?
Regards
Charmaine
Hi there. Ive been trying to coat my MAP crystals to protect them. I’ve used a few lacquer sprays, and there’s definitely an reaction. Some say to use acrylic, which is water based. Will that affect the crystal? Also how important is it too rinse the crystal. If not rinsed properly, would this affect the crystal when applying the sprays etc.
Regards
Charmaine
Water based coating might be problematic since the MAP crystals dissolve in water. The facets of your crystal will probably be less sharp as a result. Also, don’t rinse the crystal with water before applying the coating. Instead, just wipe it dry with a filter paper/tissue and let it sit in the air for a few hours before applying the coating.
I’ve actually never used acrylic sprays before, so I can’t give you a definite answer on that.
By the way, MAP crystals are stable, which means they actually don’t need any coating at all! You only need to apply coating if you want it to be more scratch/water resistant.
Hi chase, this is Aaron, How do you properly filter your solution, thanks. E-mail me at aalonaboy74@hotmail.com🙂
You just pour the solution through a coffee filter/filter paper/tissue paper, placed in a filter funnel. It’s crude, but I use it all the time, and definitely good enough for hobby-level crystal growing purposes.
What is the weir substance that is growing above the solution
That is crystal crust. The crust actually consists of MAP crystals as well, and grows because of the water evaporating on the surface of the solution as well as capillary action. This forms a layer of weird looking crystals.
Should I remove the layers of the crystal that is forming in the solution
Don’t remove them. Just transfer the solution together with your main crystal into a new container.
Trying to remove these layers will cause lots of tiny crystals to flake off into your solution, causing chaotic growth.
Should I put a lead on top of the container when I am done making the solution?
If you are not growing anything in the solution and you just want to store it, then definitely put a lid.
If you are growing a crystal in the solution, then put a lid for the first few days before removing it. Put the lid back on if you think the crystal is growing too quickly and causing the quality of the crystal to decrease as a result. Remember that generally, crystals that grow faster will tend to have more defects.
Hey chase! My partner is really into prismatic light catchers. I’ve been looking at getting reagent grade MAP to create super clear monocrystals for this purpose so you have any recommended suppliers. I found a listing from Bean Town Chemical for 35$ per 500g. Seems like a really good deal based on other listings I’ve seen.
I would also be curious if you know of any crystal that might be relatively easy to grow that would be better suited for this purpose. Perhaps something sturdy enough to facet for better light prisiming goodness?
Thank you so much this guide has been life changing!
Hello! Unfortunately, almost all the crystals we can grow at home are brittle, and not suitable for cutting or faceting. Quartz crystals might do the job, but they are not soluble in water under ordinary conditions, so growing them requires industrial autoclaves.
If you want crystals that can act as good prisms, check out my guide on growing alum crystals. They are roughly as hard as MAP crystals, but their shape makes them more suitable to refract light into beautiful patterns. I’ve got a few pics of light patterns inside that article too.
Thanks for the information Chase. I am interested in growing spiral crystals for laser experiments. Is it possible to grow them with the evaporation method? Calcite would be preferable but I could use salt crystals as well.
Calcite is made of calcium carbonate, which is not soluble in water. Therefore, it’s not possible to grow them that way. Perhaps under sufficiently high temperature and pressures like industrial autoclaves – but not practical for the average person. Salt crystals are much easier to grow. I wrote a guide on how to grow table salt cubes. However, they’re not really shaped like a spiral. Maybe you want to give pyramid salt a try?
Are these crystals pretty fragile? For some reason I feel they would be.
The sharper ones are very fragile, and snap off easily. The thicker single crystals are much hardier.
Chase,
I just started reading your blogs. This is great information for beginners like myself. Just wanted to say thank you for sharing your knowledge. I look forward to trying these in the future.
Yay, I’m happy you liked it. Good luck on your future attempts.
Hi! I am enjoying your site, and learning much! So far, I’ve made blue (light turquoise, really) epsom salt clumps that I plan to grow larger, and “coated” a strip of deep purple fabric with clear borax crystals.
For decor purposes, I’m trying to make a roughly one-inch strip of purple crystals that might look like a natural “vein” of amethyst, with one flat side, to put on the wall (without having to buy chrome alum – ha). So I’m trying lots of different things. I have violet food coloring, but I haven’t used it yet; I’m trying to just “learn the crystals” and get a good habit, first.
I have two questions, at this point, that I hope you or someone else can answer. I hate to bother you, but I’ve Googled and read a good bit, and didn’t find a definitive answer.
1) Could I add alum to a borax solution, and make the habit of borax crystals grow more elongated, also?
2) What will prevent crystal formation on a submerged surface without hurting the solution? A thin coat of wax? Oil?
Thank you for this great blog!
Hey Susan. Congrats, looks like you’re having fun 🙂
1) Adding borax to alum will cause the natural crystal structure of alum crystals to turn cubic. This means that you’ll grow alum cubes instead of octahedrons. The crystals will also become less transparent for some reason.
2) Generally, smoother surfaces discourage crystal growth while rougher ones encourage it. Try roughening up the places where you want crystals to grow. If this isn’t possible, then just let a thin layer of crystals grow over the entire object, then remove it from solution and immerse the parts of the object where you don’t want crystals to grow in tap water (hence dissolving them) and placing it back into the crystal growing solution.
Good luck.
Hi I made your crystals many times but, there is nothing so, i put 100 ml of map fertilizer then i put 150 ml of hot water i poured the water into the jar then left it alone for 1-2 hours then i added alum powder then the next day i don’t see any thing only the powders in the bottom of the jar please help me.
Try sprinkling some MAP powder into the solution. Sometimes your solution is saturated but there is no nucleation site for the crystals to start growing. If crystals still won’t grow after a few hours, this means that your solution is undersaturated. Try reheating the same solution and dissolving 20g more MAP inside. Then repeat the same process.
can you please tell me how much ml of the map do i have to put in
About 20% more than what you put in previously by mass.
Hi Chase,
You are doing an amazing and inspirational job!
I’ve made some MAP cystals and used varnish spray to protect them. However, the result is not good because it decreases the natural shine of the crystals and they turn like plastic crystals.
Is it mandatory to use a varnish in order to protect the MAP crystals or they are stable in air (no hygroscopic neither oxidize)? Do you know?
Kind regards,
Wagner
Thank you! MAP is actually completely stable in air and requires no coating.
Hi. Have you had any experience with using MKP. If so, does it grow better crystals than MAP?
I’ve never used MKP before, but it is also a very popular crystal growing compound that gives great crystals very similar to MAP.
Awesome. Thanx so much
Hi, I try to make the crystal but the first time there’s no seed at all. Then I try to follow your suggestion. Now I got a lots of thin long crystal stacked on each other instead of growing. Now I don’t know what’s wrong with it. Please help.
Are you trying to grow single crystals or crystal clusters? If you are trying to grow single crystals, then you added too much alum to make them thin and long. If you are trying to grow spiky clusters, then you need to make the solution more supersaturated. Only then will they grow into spiky clumps instead of being stacked on each other. Adding a pinch of MAP powder and stirring it around helps to induce nucleation.
Hey, so I made some seed crystals with MAP after waiting for a long time (which was where I should have notice something was wrong) and then I used that seed crystal to grow in a growing solution (45g/100ml) and the crystal dissolved. lol.
So, is it because the one I bought was not anhydrous? If so, how can I use this one to grow crystals?
Also, is there a way to store seed crystals (not just MAP, but even copper acetate, etc) somehow so I can use them later? Or do I have to use them fresh?
Thank u so much for taking the time to answer my questions.
The crystal dissolved because your growing solution was not concentrated enough. 45g/100mL is just a guideline, because the solubility of MAP can change depending on the temperature of your place. To make sure this doesn’t happen, try adding a tiny pinch of MAP powder to the growing solution before you put in any actual crystals you want to grow, and wait a few hours. If the pinch of powder doesn’t dissolve, then it’s safe to add the actual crystal inside.
By the way, MAP is always anhydrous. It contains no water of crystallization.
Yes, just dry the seed crystals and keep them in a container. Copper acetate requires an airtight container to prevent dehydration. Fresh MAP seed crystals might give a more transparent and higher quality result. It doesn’t matter for copper acetate, because the color is so dark.
Hmm, ok. thanks a lot!
How does humidity affect the crystal growth rate?
High humidity slows down evaporation, which decreases the growth rate. Don’t worry, you can still grow crystals at high humidity. I’ve grown amazing ones at 80% humidity.
Thanks!
Very informative and detailed website. I absolutely loved every bit of it. Thrilled to make some crystals sometime in future.
Hi there. Desperately need some help. I got ADP from a new supplier. I’m just not able to even grow proper seeds. I’ve posted pics etc on Reddit. Username Charmz1965.
Aight. I’ll look for you on Reddit.
Hi. So this ADP, still haven’t managed to grow proper seeds etc, has such a strong chemical smell. Would you know why. The ADP I got previously from the other supplier was odorless.
In that case, the normally odorless ADP is probably contaminated with some impurity. By the looks of it, it also inhibits crystal growth. I’d encourage you to get ADP from a different supplier.
Have you ever tried to create a silicone cast of a MAP crystal? I’d love to grow some neat clusters to cast in silicone for resin projects. It’d probably be less expensive to make crystal of the size abd shape I want than to buy real crystal clusters.
That’s a very good idea! You’re the first one to suggest it. That would also fix the problem where the crystal would dissolve in water. I’ve had no experience with making silicone casts before, but I’ll definitely take a look.
Amei todas as instruções que você deu aqui. Muito obrigada. O que é alúmen? Tem um outro nome?
Obrigado. Também é chamado de sulfato de alumínio e potássio.
This website is awesome! I’ve always been fascinated and a fan of growing crystals myself (on a much smaller scale). So I can’t wait to try attempting growing such a beautiful large crystal with your tips! 🙂
Good luck!
I put some ADP CP grade crystals into saturated AR grade and they dissolved.
Generally, this should not happen. Separately, try making saturated ADP solutions of the two different grades of chemical. Let them crystallize. See whether their crystals look different from each other. This should tell you whether they are indeed ADP, and how pure they are. If you are still unsure, you can host pictures on a website like Imgur and send the link here. For now, I suggest you don’t mix the two.
Hi there. I find when I’m trying to filter my ADP solution, while it’s still hot, it starts to crystallize almost immediately, to the extent that I can’t even filter it. I’ve followed the measurement, so not sure what I’m doing wrong.
It means your solution is too saturated – to the extent where crystals start forming even while the solution is hot. Try to add a little more water to lower the concentration before filtering.
Hi there. Have you had any experience with growing crystals with Potassium dichromate?
No, I’ve never grown crystals with it before, mainly because it’s quite toxic.
Is it possible to make crystals with diammonium phosphate instead of monoammonium, and if yes do i follow the same procedure as the monoamonnium crystals?
I’m not sure. Although they are similar, I’ve not seen anyone growing crystals from diammonium phosphate which implies that it might not crystallize well.
Ok thanks for the info, i will try if i can make some crystals with it
Hi there. After I’ve dissolved the ADP and add my bit of alum, the mixture goes white, and then after I’ve filtered the solution, there’s a white foam type consistency left behind. Is this normal?
Yes, this is normal. It’s due to impurities in the water/ADP that you used. Don’t worry, just leave it for a few days, let it settle out and filter the solution again. Then it will stay clear.
Thank you so much
Thank you for amazing detailed journey. Am trying to buy MAP as a fertilizer and I am getting options for NPK ratio like 12:61:0 or 20:20:20.
Please advise!
Use the 12:61:0 one. Monoammonium phosphate contains no potassium, hence the 0.
Hi there. None of my garden suppliers had MAP. I ordered some online, but just realized it’s sulphate and not phosphate. Is this going to work still?
Hi. Can you send me the link, so I can check?
Hope this helps.
https://growguru.co.za
And I bought the ammonium sulphate
I see. Ammonium sulfate can indeed form crystals, but they are not very nice. However, you can combine ammonium sulfate with sulfates of other compounds to form double salts. For example, if you mix ammonium sulfate with iron sulfate, you get Mohr’s salt, which forms beautiful light green crystals. Mix it with aluminum sulfate, then you get ammonium alum, which forms clear octahedral crystals. The growing procedure is similar to regular potassium alum.
Thank You for sharing knowledge! Now the the stepsons have family time planned… with your idea and step by guide, it’ll surely get them away from the tv and and interested in science. All I knew how to make at home were to mix a household cleaner in some tin foil, put it in a plastic bottle and screw the lid on tight let it go boom! That wasn’t safe for the kids but THIS will be perfect. If you have any at home crystal growing projects, please put them into a step by step process and we’ll try them. Are there any at home grown crystals used for jewelry or negative energy removal?
Yes, it’s always important to keep safety in mind. Most of the crystals I show are relatively safe, but some (especially the copper ones) are toxic when eaten so it’s a no-go for young kids. I’ll try my best to share my latest discoveries here.
Nearly all of the crystals you can grow at home are water soluble, so they cannot be used as jewelry. However, you can check out bismuth crystals. Since they are made of metal, bismuth is insoluble in water. They are very beautiful and easy to grow at home. Although I have never made any myself, there are lots of guides online that you can check out, and maybe give it a shot.
Hello Chase!
First of all, thanks for all the amazing guides!
I’m currently trying to grow some crystals, but MAP isn’t widely available where I’m from, so I was wondering if it was possible to recycle and reuse seed crystals and the crystal powder that forms at the bottom of the beaker?
And if so, how would you do this?
Yes, it is definitely possible, even recommended to recycle the crystals. When you want to make a new batch of solution, just put the unwanted crystals in with your MAP powder to dissolve like usual.
Awesome guide, I’ve managed to make a number of different crystals from this guide.
The main issue I’m facing now is finding materials. Getting hold of MAP is becoming really hard, there doesn’t seem to be much on Amazon, and I’m not super keen on buying from Aliexpress with a minimum order of 10 tons. Any suggestions on where to source it?
Hello there. Where do you live? Try finding MAP under different labels, like ammonium dihydrogen phosphate (ADP) or nitrogen fertilizer. It’s the same stuff, but labelled differently. Plus, most of the time, getting MAP sold as fertilizer is much cheaper than MAP sold as just the compound.
You can also look into potassium dihydrogen phosphate (KDP), which is a different compound but looks almost identical. Furthermore, the procedure to grow it is also exactly the same.
If you can’t find the stuff you need on Amazon, maybe you can try Ebay? Some people have said that it’s cheaper for certain chemicals.
Hey,
im having some issues after stirring in a pinch of map in the solution, i end up with a lot of map powder at the bottom of my jar..
Do you know why this is and how to prevent it?
Hello. Do you mean more MAP powder formed compared to the pinch that you added in? This is actually exactly what we want – to cause lots of powder to form that will generate seed crystals.
However, if you’ve waited several days, and no crystals have formed (just powder sitting at the bottom), then there’s 2 things you can do.
1) Reheat the solution to dissolve the powder inside. Add a bit of alum. Repeat the exact same procedure. This should guarantee that the next time you drop in a pinch of powder, the powder will turn into a cluster of crystals, as shown in the pictures above.
2) If you don’t have alum, or if you just want to grow single crystals, no problem. Simply decant the solution into a new container, leaving the bunch of excess powder behind (which can be recycled). After that, you just have to put it in a shaded place and single crystals will form.
Feel free to ask if you have further questions.
Fantastic guide! Very instructive. I’ll try this out as soon as I can gather the materials.
A question that came up: From what you explained, adding more allum (acidifying the solution) will result in spikyer crystals. Do you control the acidity by the amount of dissolved allum, or do you also check the pH of the solution using pH strips?
Asking because I’m concerned about getting different results since the average pH of tap/drinking water differs from country to country, so knowing the pH ranges used in crystals 1-6 would be interesting.
Thank you!
I completely agree with you that pH is a better method to determine the effect of acidity on crystal shape. But when I was doing the experiment, I didn’t have any strips on hand. (All this while I was using just the amount of alum as reference.) I’ll remember to update this information in the guide when I’m able to.
Good luck!
What an awesome site! Thank you so much for this I’m going to have so much fun doing this 💗
This is such a great site! I love how all the steps are detailed enough to follow. So glad I saw your post on Reddit! Now time to experiment with the kiddies! Thanks for taking the time to do this.
That’s awesome! Make some happy memories together.
Thank you for introducing me to a world I never knew about, and being so generous with your knowledge. I hope I can find the “ingredients” locally as I will definitely be trying this.
You’re welcome, and good luck 🙂
Hey man, thank you very much for this guide. I was going to try crystal growing with my 4 years old daughter but coudn’t find a proper etailed guidance online. I saw your post on reddit and that brought me here.
I just have a couple of questions: Is the colour you used simply food coloring, or is it a special type of colour? Is there any special moment in the process when you should add the colour?
Hello. I just used regular food coloring. You can add it at any point before the crystals form, because you obviously need to color the crystals. But I like to add mine right after I prepare the saturated solution, and before I filter it.
Hello! Trying out my first batch right now. Im stirring in a non stick pot because I dont have a large enough container for the growing solution to sit in and cool until I transfer. Will that hamper the results? Als, my seed crystals didnt look nearly as well kept as yours.
The pot will do. Just remember not to leave it inside for too long, as MAP is a type of salt. And like table salt, super concentrated solutions of it can be corrosive to your pot.
I picked my best seed crystals to take photos with haha. The best thing about MAP is that the seed crystals don’t have to look nice at all. If you add the appropriate amount of alum and grow the seed crystal slowly, then your crystal will turn out beautiful.
Can you please make a guide how to grow a crystal from iodine?
Hey there. I don’t have any iodine on hand at the moment, but I’ll keep that in mind. The crystals that form via sublimation are thin, fragile and very pretty.