My wife loves getting crafty, so when we first got into hydroponics, I knew it was only a matter of time until we made our own.
One of the easiest ways to get into DIY hydroponics is through mason jar hydroponics.
In this article, we’ll go over everything you need to know about setting up your indoor hydroponic system for cheap and growing plants and herbs in your home in no time.
Table of Contents
Materials Needed For Mason Jar Hydroponics
While you’ll save on money by using more affordable alternatives, there are some things you’ll need to get:
- Net pots with sizing matching your mason jar lid (Available here)
- Mason jars
- Clay pebbles or another growing medium (Available here)
- Rockwool (Available here)
- Seeds for your plant
- Hydroponic fertilizer (Available here)
- Chalk paint
- Grow lights if not placed in a sunny spot (Available here)
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Germinate Seeds In Rockwool Growing Cubes
The first step is to get your seeds to sprout.
Get out your Rockwool cubes and widen the hole in the middle.
Put two seeds in the hole and gently push them in toward the center of the cube.
Pinch the top closed and soak the cube with hydroponic solution (follow the directions on the product you buy for the exact amount and mixture).
Pro-tip: Put the cubes on a tray to prevent water from going everywhere.
You want to put enough water in that it starts to leak out the bottom.
Cover up the cubes to keep the air as moist and warm as possible.
Check on it daily (no water should be needed) until you see sprouts.
Depending on the plant, this may take between 2 days to a week.
For more details, check out our guide for how to use Rockwool with hydroponics.
Prepare The Mason Jar
While the seeds are germinating into seedlings, we want to prepare the mason jar for the plant.
Paint or cover the outside of the jar so you don’t see through. Black works well, but any dark color will do the job.
We want to prevent light from getting to the water as this will promote algae.
Pro-tip: Chalk paint on the exterior isn’t necessary (any paint will do), but if you use it, you’ll be able to use chalk to mark up the exterior and label what you’re growing.
At this point, you’ll also want to make sure you clean and rinse the interior of the jar well, making sure there’s nothing inside it.
You may also want to rinse off your growing medium at this point.
Put Growing Medium In Net Pot
Put a small layer of your growing medium in the bottom of the net pot.
We’ve had great success with clay pebbles, and this is the standard for most hydroponic systems.
However, cut-up Rockwool pieces will also do the job. Just make sure you soak them to lower their pH level and remove the natural salt in the product.
Transfer Seedling To Net Pot
Transfer your seedling to the net at this point and fill in the rest to the top of the pot with the growing medium.
The growing medium will provide for the roots as your plant grows, and it’ll help to hold extra moisture.
Yogurt cups are a homemade net pot solution if it’s made of safe plastic.
Check out our guide to safe plastics for hydroponics for more details.
Skewer the yogurt cup with wooden dowels to help dangle the cup into the mouth of the mason jar and cut slits all over to encourage air circulation.
Don’t forget to cut off the bottom to allow for growth.
(But net pots are so cheap, you may as well just buy those.)
Mix Hydroponic Solution And Add To Jar
In a separate container, mix up your hydroponic solution according to the instructions on the specific product you buy.
Don’t be surprised if you only add a drop or two of the fertilizer.
Overnutrition is even more dangerous than undernutrition with plants.
If you have soil fertilizer, it’s possible to use it in a water solution if you go about it the right way, though we don’t recommend it.
If you really want to try it, check out our article on using normal fertilizer for hydroponics.
Use distilled water or water without chlorine or chloramine (as used with treated tap water).
For a home fixture with tap water, leave the water in a bucket out in the sun for 24 hours or cut up a lemon and leave it to sit in the water for 24 hours.
Add the water to the jar, so the roots are submerged in the water with a 1/4-1/2″ inch gap between the water and the body of the plant.
Put the net pot on the mouth of the mason jar.
Put In Sun Or Use Grow Lights
Move the mason jar into direct sunlight or underneath the grow lights.
If using grow lights, keep it 2-3″ inches above the leaves of the plant, but don’t let the leaves touch the light.
Adjust the height of the grow light as your plant grows and adjust upwards as needed.
If you are using sunlight, you don’t need to worry about this.
Check Water Daily
Check on the water every day.
If the water dips below the roots, add more back up the 1/4-1/2″ inch gap below the plant. This air gap oxygenates the plant and helps with growth.
Any water you add at this point should have NO nutrients added.
If the roots stretch down the jar quite a ways, add more water when the levels get halfway down.
The second time the water gets halfway down, remove the net pot (gently!), dump the water out, wash if needed, and add more hydroponic solution.
Repeat Until Harvest
Repeat this process until your plants are ready to harvest.
Some grow much faster than others.
In general, plants grown hydroponically mature to harvest faster than soil growing.
If you’re new to growing hydroponics, we encourage you to stick with herbs or lettuce to get a feel for it.
If you want to skip the making of your own system and get used to how it all works, check out our reviews of the best AeroGarden for lettuce and small herbs.
Video For Hydroponic Mason Jar Setup (With Timestamps)
For those of you who prefer to learn by watching, check out this quick video on how this person sets up her hydroponic mason jar.
Use the timestamps below to help you skip around.
- What You’ll Need – 0:20
- Fill Net Pot With Growing Medium – 1:00
- Add Hydroponic Solution – 2:20
- Prepare The Mason Jar – 4:25
Commonly Asked Questions
What Fruits And Vegetables Work Well With Mason Jar Hydroponics?
First, you have to consider the size of your mason jar.
Some plants have more extensive root systems than a mason jar can handle.
Hydroponic apple trees, for example, are way too big to grow in a jar.
If you want to learn more about it, click the link to our article.
Smaller plants work best in mason jars, so you’re looking at things like:
- Cherry Tomatoes
What Cannot Be Grown Hydroponically?
Root vegetables don’t do well in this system. They need the dark and moisture, and soil to flourish.
Plants such as:
What Is A Kratky Jar?
Technically, mason jar hydroponics is a Kratky Jar.
The Kratky method is a hydroponic system without an air pump where you oxygenate the water by leaving an air gap between the plant and the water.
This is an easy-to-use method, as you’ve seen from the setup article here.
This method becomes tougher the more plants you have and the larger the root systems.