You can create a cost-effective indoor hydroponics setup by using mason jars, allowing you to cultivate plants and have your own vegetable or herb garden at home.
Hydroponically grown plants use water instead of soil to grow (which certainly cuts down on the mess), but this simplified method can still take a bit of trial and error to get just right.
To help you get everything in place for starting your own successful mason jar hydroponic garden, we’ll walk you through each step in detail.
We’ll also share our top tips for long-term care, troubleshoot some common issues, discuss the best mason jar plants to grow, and more!
Supplies Needed
- Wide-mouth mason jars
- Seed starter plugs
- Nutrient mix
- Net/mesh pots
- Growing medium (clay pebbles)
- Heat mat (optional)
- Grow light (optional)
- Misting bottle
- Blackout material (black acrylic paint/aluminum foil)
- Toothpick
- Wooden skewer
- pH testing kit
- pH adjuster kit (optional)
- Nutrient testing kit (optional)
How To Set Up a Mason Jar Hydroponics System
Follow the simple steps outlined below to get your plants off to a great start in a mason jar setup (based on the Kratky system).
1. Start Seeds & Allow 4-14 Days for Germination
As your plants need roots to absorb the water in the jar, you’ll need to start them separately as seeds first.
Place your seeds of choice onto a plate, and dip a toothpick in clean water. Using the toothpick, pick up individual seeds and place 2-3 into each seed starter plug.
Moisten the seed plugs lightly with a spray of water. Keep the seed plugs covered in a dark, humid location, and depending on the type of plants, allow up to 2 weeks for them to germinate.
Tip: A heat mat can help speed up germination!
2. Choose a Wide-Mouth Jar & Paint the Outside Black
Select a wide-mouth mason jar — this makes it easier to clean and retrieve your plants when necessary.
Light passing through the jar promotes algae growth, so make the outside of the jar opaque to block out light, ideally using black acrylic paint or spray paint (You could also wrap the jar in duct tape, blackout cloth, or aluminum foil!).
Cover the screw ring/threads of the jar in tape and surround the jar body in your chosen blackout material. Allow it to dry fully.
3. Select Net Pot in Corresponding Jar Size
You’ll then need a net cup to hold the seedling in the top of the jar so the roots can access the water line. Choose the right net pot size so it fits snugly into the lip of the jar (3-inch pots are normally best for most wide-mouth jars).
4. Make Nutrient-Rich Solution & Fill Jar as Needed
Prepare your hydroponic nutrient solution according to product instructions, such as 1 tsp. per gallon of water, and fill the mason jar close to the base of the net pot.
Keep in mind that it’s best to use distilled water. I explain why here.
Net pots are usually 1 inch deeper than they are wide, and you’ll need a small gap of air between the water line and your pot so the roots can hang in the water, so adjust the water amount as needed.
5. Transfer Seedling to Pot & Add Growing Medium
After 2 weeks your seedling should have roots sprouting through the plug base. First, add a few clay pebbles to the bottom of the net cup.
While still in its starter plug, place the seedling in the center of the net pot, and surround it with the clay pebble medium (hydroton) to help your plant absorb the nutrients.
6. Place in Bright Location & Check Water Levels Regularly
Put your mason jar seedling in a sunny location. Check the water levels every week or so to ensure the roots are always partially submerged in the nutrient-rich water.
Tip: Use a slim wooden skewer to poke down into the base of the jar and check when the water needs replenishing.
Caring for Hydroponic Plants in Mason Jars
So, the initial steps are done… now it’s time to give your plants the proper care they need to thrive.
Changing the Water
As the roots drink up the water, your mason jars will need to be topped off with water now and again to ensure they’re submerged.
Once these water top-offs start to equal the entire volume of water in the jar, it’s time for a full water change. Changing the water any more frequently than this can risk shocking the plant and stunting its growth.
Adding the Nutrients
The directions on your chosen bottle of hydroponic nutrients should state how much and how often your plants need plant food.
In the case of herbs with a quick maturing period like basil, a single feed should provide all the necessary nutrients, but larger leafier plants may need feeding every 2-3 weeks.
Let There Be Light!
A bright sunny location like a south-facing window is ideal for your mason jar garden, but not everyone has access to great natural sunlight in their homes. This is where artificial grow lights are a must.
Invest in a grow light that provides full-spectrum light, ideally with a timer and adjustable mechanism so the light can be tilted or positioned where needed.
Bear in mind that hotter grow lights will mean faster evaporation and more frequent water top-offs and changes.
Testing pH Levels
Each plant you grow has an ideal pH range in which they thrive, so it’s helpful to have a pH testing kit for your mason jar garden.
Herbs, for example, prefer pH levels between 5.5 and 6.5, and water changes and nutrient top-ups can throw this out of balance.
A little trial and error may be needed based on your tap water’s natural pH and how the nutrient solution affects things before you’re able to determine the ideal levels for your plants.
Keep a record of these pH levels so you know how strong or weak to make the solution to avoid endless future testing.
Best Plants for Mason Jar Hydroponics Garden
Herbs are ideal for hydroponic mason jar gardens as are small, manageable leafy plants like lettuce and spinach.
Larger veggies like tomatoes and beets may be possible, but you’re going to need a bigger mason jar! Here’s a list of the best plants to start with:
- Basil
- Chives
- Parsley
- Watercress
- Mint
- Rosemary
- Lemongrass
- Thyme
- Cilantro/Coriander
- Oregano
- Dill
- Lavender
- Fennel
- Sage
Alternative Method – Wick System for Mason Jar Hydroponics
The Wick hydroponics system still uses a net pot and a mason jar as a water reservoir, but in this method, the roots are kept in a growing medium and do not touch the water.
The water is instead soaked up via nylon paracord rope that is threaded through the net pot basket to wick water and drip onto the plant roots.
Problems You Might Encounter (& How To Avoid Them)
With your first attempt to grow herbs or leafy plants, you might run into common issues. Things might go perfectly, but any problems that do crop up should be viewed as a valuable learning experience.
Here are a few commonly encountered setbacks:
- Rotten Roots – Your growing medium may be too compacted. Consider porous mediums like clay pebbles, rockwool, or coconut fiber for ideal drainage.
- Slow or Stunted Growth – Plant leaves could be crowding each other, so keep them trimmed. Be sure to keep plants in adequate lighting for their needs.
- Yellowing Leaves – Discolored leaves despite clean water changes may indicate a pH issue. Test pH levels, and consider stronger/weaker nutrient solution.
- Algae Growth – Take care not to overfill jars with water, and reduce the amount of light. You could also add an algae inhibitor to the water.
Frequently Asked Questions:
What Nutrient Solution Is Best for Mason Jar Hydroponics?
Most general liquid nutrient mixes will work well for small-scale mason jar hydroponics systems. General Hydroponics Flora Grow and AeroGarden Liquid Plant Food are both frequently recommended.
Do I Need To Adjust the pH of the Nutrient Solution?
Certain plants grow best in specific pH ranges, and due to the chemical formula, the hydroponic nutrient solution typically lowers the pH of water, so check to see if levels need adjusting after the nutrients have been added.
Ph adjuster kits can help you do this if necessary.
How Often Should I Change the Nutrient Solution?
You may need to change the nutrient solution every 7-21 days, but the frequency will depend on the rate of nutrient depletion.
To monitor nutrient strength in the water, you can use a nutrient testing device. General Hydroponics advises that nutrient strength runs between 800 and 1500 ppm (parts per million).
Can I Use Natural Sunlight for Mason Jar Hydroponics?
Where possible, direct natural sunlight is best (a sunny south-facing window of 6 hours of daily sunlight is perfect).
Many plants require at least 6 hours of direct sunlight, so shadier conditions will need to be supplemented with grow lights for adequate growth.
Can I Grow Larger Plants Using Mason Jar Hydroponics?
Growing larger plants will require gallon-sized mason jars or larger ones.
Technically, large plants like tomatoes, peppers, and beets can be grown using this hydroponic system, but using an opaque tub or tote for the reservoir may be more appropriate to accommodate larger root systems.
How Much Does It Cost To Set Up a Mason Jar Hydroponics System?
This hydroponics system may cost a little over $50 to purchase all new supplies (grow light, nutrient mix, seed starter, etc.).
However, if you already have good natural light and old mason jars, then costs may come to $30 or less — it all depends on what you’re willing to spend and where you’re willing to go DIY!
Can I Use Recycled Mason Jars for Hydroponics?
Yes, you can absolutely upcycle old mason jars! Just ensure they are intact (no cracks or damage), and thoroughly disinfect them before use.
Sterilize old jars in Lysol or bleach to eliminate potentially harmful bacteria, and always opt for wide-mouth jars where possible as these are easier to clean.
Enjoy Your Mason Jar Hydroponic Garden!
From germination to maturity, the entire process of growing mason jar hydroponic plants can take about 2-3 months. This will vary based on the individual plants, growing medium, specific nutrients used, etc.
You’ll know you’re on the right track if your plants have achieved noticeable growth after a week and are producing decent water roots (below the water line) and substantial air roots (in the net pot).
Plants growing strong in an upright direction is also a great sign, suggesting adequate light exposure on all sides.
It will, of course, take a little experimentation to get the water, pH levels, and sunlight needs just right for your chosen herb or veggie, but you can always refer back to this mason jar hydroponics guide if needed.
Have fun with it, and don’t lose hope! Happy indoor gardening!