The Kratky method is the closest thing hydroponics has to a free lunch: fill a jar, drop in a seedling, walk away. No pump, no airstone, no power bill. The downside is most "Kratky kits" on Amazon are just three mason jars in a box. We tested five — from the bare-bones jar packs to the multi-plant tubs — and here are the ones actually worth buying.
The short answer
- Best overall: a wide-mouth mason jar + 2-inch net pot + hydroton starter pack. About $25 all-in and lasts forever.
- Best for lettuce volume: a 12-pod countertop kit run pump-off (yes — the iDOO works as a giant Kratky tub).
- Best for classrooms: a multi-jar starter pack with pre-cut lids.
Kratky kits compared
Last checked: June 2026 · affiliate disclosure
| Product | Power needed | Refill cycle | Best for | Where | ||
|---|---|---|---|---|---|---|
Wide-Mouth Mason Jars (1-quart) Editor's Pick | 1 per jar | None | Once per crop | $25 | Lettuce, basil, single herbs | Check price |
2-inch Net Pots (50-pack) Cheapest add-on | 50 pots | None | n/a | $12 | Pair with jars you already own | Check price |
Hydroton Clay Pebbles Reusable medium | Enough for 30 pots | None | Rinse and reuse | $20 | Anyone scaling past 3 jars | Check price |
iDOO 12-Pod Hydroponic Kit Best for volume | 12 | Optional (LED only) | Every 3–4 wk | $89 | Salad-bowl harvests, pump-off | Check price |
General Hydroponics MaxiGro Essential nutrient | Hundreds of gallons | None | 1 tsp/gal | $20 | Every Kratky setup | Check price |
- Plants per kit
- 1 per jar
- Power needed
- None
- Refill cycle
- Once per crop
- All-in cost
- $25
- Best for
- Lettuce, basil, single herbs
- Plants per kit
- 50 pots
- Power needed
- None
- Refill cycle
- n/a
- All-in cost
- $12
- Best for
- Pair with jars you already own
- Plants per kit
- Enough for 30 pots
- Power needed
- None
- Refill cycle
- Rinse and reuse
- All-in cost
- $20
- Best for
- Anyone scaling past 3 jars
- Plants per kit
- 12
- Power needed
- Optional (LED only)
- Refill cycle
- Every 3–4 wk
- All-in cost
- $89
- Best for
- Salad-bowl harvests, pump-off
- Plants per kit
- Hundreds of gallons
- Power needed
- None
- Refill cycle
- 1 tsp/gal
- All-in cost
- $20
- Best for
- Every Kratky setup
What makes a good Kratky kit
- Opaque or wrapped jar. Light hitting the reservoir = algae within a week. Use amber jars or wrap clear ones in foil.
- Wide-mouth opening (≥3"). Standard mouths don't fit a 2-inch net pot snugly.
- At least 1 liter of reservoir per plant. Smaller and you'll be topping off mid-cycle (which defeats the point).
- A nutrient packet or recommendation. Plain water grows nothing. MaxiGro at 1 tsp/gal is the no-brainer answer.
1. DIY mason jar kit — Best overall
Twelve wide-mouth quart jars, a 50-pack of 2" net pots, a bag of hydroton, and a tub of MaxiGro. Total: about $55 for a setup that grows 12 lettuces simultaneously and will outlast you. Wrap each jar in a strip of duct tape or foil to block light. This is the kit we recommend to 90% of readers.
2. iDOO 12-pod kit — Pump-off Kratky in disguise
Unplug the pump, leave the LED on, and the iDOO becomes a 12-plant Kratky tub. The reservoir is sized perfectly for a single lettuce cycle without a refill, and the built-in LED solves the "where do I put it?" problem most jar setups have. The best Kratky "kit" you can buy if you want one box on a shelf.
3. Pre-cut Kratky jar packs (Amazon)
Six-jar packs with lids pre-drilled for net pots. Convenient for classrooms or gifts, but you're paying $40+ for what you can build for $20. Useful if you don't own a drill.
4. 5-gallon bucket Kratky kits
One bucket + 3-inch net pot lid grows a full head of romaine or kale for under $15. The cheapest cost-per-pound option, but ugly — keep it in a basement or grow tent. Skip the kits marketed as "complete" and just buy a Home Depot bucket plus a drilled lid.
5. What we'd skip
Avoid any "Kratky kit" that ships with peat plugs only (no rockwool option), no nutrient, or jars under 16 oz. They're priced like toys and perform like them.
Free: The 12-page Indoor Hydroponics Starter Guide
Everything we wish we'd known before our first harvest — equipment, seeds, nutrients, and a 4-week plan you can actually finish.
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What to grow first
Buttercrunch lettuce. It germinates in 3 days, is impossible to over-fertilize at 1 tsp/gal MaxiGro, and gives you a full head in 28–35 days. Once you've nailed it, branch into basil, cilantro, and bok choy.
Related guides: The Kratky Method, Explained Simply · Best Hydroponic Starter Kits for Beginners · how-to-grow-lettuce-hydroponically
Frequently asked questions
Does Kratky really need zero electricity?
Correct — no pump, no airstone. The plant's roots grow into the air gap above the falling water line and self-aerate.
Can I grow tomatoes with Kratky?
Technically yes (in a 5-gallon bucket), but yields are poor compared to a DWC or Dutch bucket. Stick to lettuce, herbs, and bok choy.
Why is my reservoir green?
Algae from light exposure. Wrap the jar in foil or duct tape and the problem disappears.
Do I refill the jar mid-cycle?
No. A correctly sized jar holds enough solution for the entire crop. Topping up disrupts the air gap and stunts roots.
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