Kratky Supplies Checklist
This Kratky supplies checklist covers everything a passive hydroponic system needs. Some items come in most kits, some you will buy separately, and a few are optional extras that make life easier.
The essentials
1. A container (reservoir)
Holds the nutrient solution. It should be food-safe, opaque or covered so light cannot reach the water, and large enough for the plant you want to grow. Mason jars, plastic storage totes and buckets all work. The Kratky containers guide covers sizes and light blocking.
2. A lid with holes for net pots
Supports the plants above the solution and keeps light out. Kits come with fitted lids. For homemade systems, a lid can be cut with a hole saw to match the net pot size.
3. Net pots
Mesh cups that hold the plant and let roots grow through into the solution. Two-inch and three-inch pots are the most common. Larger plants appreciate larger pots.
4. Grow media
Supports the seedling inside the net pot. Common choices are rockwool cubes, coco coir plugs, peat plugs and expanded clay pebbles. See rockwool vs clay pebbles for the differences.
5. Hydroponic nutrient
A complete fertilizer made for hydroponics, containing the major nutrients and the trace elements that soil would normally supply. Soil fertilizers are not a substitute. The Kratky nutrients guide explains how to choose and mix one.
6. pH testing and adjustment
Test strips, liquid drops or a digital pH pen, plus small bottles of pH up and pH down. Nutrient solutions often need a small adjustment after mixing. See the Kratky pH guide.
7. Seeds or seedlings
Start your own in plugs or rockwool, or use young plants. Soil-grown transplants can be used if the soil is gently washed from the roots, though plants started in plugs usually settle in more easily. See starting seeds for a Kratky kit.
8. Light
A bright window or a grow light. Indoors, most leafy crops grow better under a grow light than on all but the brightest windowsills. See Kratky grow lights.
Useful extras
- EC or TDS meter. Measures nutrient strength, so you can check that a mix matches the label and compare batches.
- Measuring syringes or spoons. Small nutrient doses are easier to measure accurately.
- A separate mixing bucket. Lets you mix and adjust pH before pouring into the reservoir.
- Light-blocking sleeve, tape or paint for clear containers.
- Plant supports. Stakes or a small trellis for taller plants.
- Labels and a marker. Note the planting date and the first fill line.
- Hole saw or step drill for cutting lids on homemade systems.
| Item | Job | In a typical kit? |
|---|---|---|
| Reservoir and lid | Holds the solution, supports the plants, blocks light | Yes |
| Net pots | Hold each plant and its media | Yes |
| Grow media | Support seedlings, wick moisture | Yes |
| Hydroponic nutrient | Feeds the plant | Often |
| pH test strips | Check the solution | Often |
| pH up / pH down | Adjust the solution | Less often |
| EC or TDS meter | Checks solution strength | Rarely |
| Grow light | Light where windows are dim | Less often |
| Air pump | Not used in Kratky | No (a kit with one is DWC) |
What most kits include
Kits vary, but a typical Kratky hydroponics kit includes a reservoir and lid, a set of net pots, grow media for each planting site, and often a nutrient and some pH test strips. Instructions are usually included. Lights, meters and pH adjusters are less often in the box. The home page lists what a Kratky hydroponics kit includes in more detail, and the guide on how to choose a Kratky kit explains what to check before buying.
What you do not need
- An air pump or air stone. These belong to deep water culture, not Kratky. The air gap does their job.
- A water pump or timer. Nothing circulates in a Kratky system.
- Soil or potting mix. It clouds the solution and can carry pests and disease.
What these parts add up to, upfront and per crop, is covered in Kratky kit cost.
Frequently asked questions
Do I need an air pump for a Kratky kit?
No. An air pump belongs to deep water culture. In a Kratky system, the air gap that forms as the water level falls supplies the roots with oxygen.
Can I use regular plant fertilizer instead of hydroponic nutrient?
It is not recommended. Soil fertilizers often leave out trace elements that soil normally supplies, and some cloud the water. Use a complete nutrient labeled for hydroponics.
Do I need an EC or TDS meter?
Not for a first jar of lettuce if you follow the nutrient label carefully. A meter becomes useful when you grow several crops, mix larger batches or want to check that a mix matches the label.
What size net pots should I buy?
Two-inch and three-inch net pots are the most common. Three-inch pots fit wide-mouth mason jars and give larger plants more support.
Can I start a Kratky kit with soil-grown seedlings?
Yes, if you gently wash all the soil off the roots first. Soil in the solution clouds the water and can bring pests or disease. Plants started in rockwool or plugs usually transplant more easily.
Printable checklist
- Container, food-safe and opaque (or covered)
- Lid with net pot holes
- Net pots, one per plant
- Grow media
- Complete hydroponic nutrient
- pH test kit, pH up, pH down
- Seeds or seedlings
- Window or grow light
- Optional: EC/TDS meter, mixing bucket, measuring syringes, light-blocking cover, plant supports, labels
With everything ready, follow Kratky kit setup to put it all together.