Container guide
Best Containers for Kratky Potatoes
The best containers for Kratky potatoes are deep, opaque and food-safe, with a lid that holds the basket and blocks light. A 5-gallon bucket suits one early potato plant, and a deep storage tote suits a bigger, later variety. This guide covers what makes a good container and how to fix the common problems.
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What makes a good Kratky potato container
- Depth: room for the basket of medium above the solution, and enough solution below it to last as the level falls.
- Opaque walls and lid: no light reaching the solution or the tubers.
- Food-safe plastic: look for a food-grade label, or HDPE (recycling code 2).
- A stiff lid: it has to hold the basket and the weight of a growing plant without sagging.
- Volume: a big potato plant drinks a lot over a long season, so more solution means fewer top-ups.
5-gallon buckets
A 5-gallon bucket holds about 19 liters, has a tight lid, and is easy to find. It suits one early variety, such as Red Norland or Yukon Gold. The catch is color: many buckets are white or translucent and let light through, which grows algae in the solution and can turn tubers green. Choose a black or dark bucket, or block the light yourself (see below).
Deep storage totes
A deep, heavy-duty storage tote holds more solution than a bucket and has a wide lid, which makes it the better choice for mid-season and late varieties, including russets. Still plan on one plant per tote. Look at depth rather than width, choose a rigid lid, and check the label, because not every tote is sold as food-safe. Black totes block light well.
Why grow bags don't work
Fabric grow bags are popular for potatoes in soil, but they can't hold nutrient solution, so they aren't Kratky containers. The same goes for any pot with drainage holes. A Kratky container has to be watertight.
The lid and basket
Cut a hole in the lid to fit your net pot or basket, using a hole saw or a sharp utility knife. At the start, the base of the basket should just touch the solution. Choose the deepest basket the container allows, because the tubers form in its medium and you'll keep adding medium as the stems grow.
Blocking light leaks
To find leaks, put the lid on, take the container into a dark room, and shine a flashlight inside. Any glow on the outside is a leak. Paint the outside, wrap it in foil tape or black plastic, or stand the container inside a larger opaque one. Close the gap between the basket and the lid with tape or a ring of foam. Light leaks cause two problems: algae in the solution, and green tubers that contain solanine; see why potatoes turn green.
Keeping the container cool
A dark container in full sun heats up, and warm solution holds less oxygen and slows tuber growth. A light-colored or reflective outer wrap keeps it cooler while the inside stays dark. Avoid hot spots such as walls that soak up the afternoon sun.
Cleaning between crops
At the end of the season, empty the container, scrub off any algae and root debris, rinse it well and let it dry before you store it. Check the lid for cracks and the basket hole for a snug fit. A clean container starts the next crop without leftover algae or the organisms that cause root rot.
Container checklist
- Deep enough for a basket of medium plus solution below it.
- Opaque, or wrapped so it is.
- Food-safe plastic.
- A stiff lid with a snug hole for the basket.
- Kept out of hot spots, or wrapped to reflect heat.
Once the container is ready, see the full list of Kratky potato supplies, then follow how to grow potatoes without soil to set it up.
Questions about Kratky potato containers
How big a container do Kratky potatoes need?
A 5-gallon bucket, about 19 liters, is enough for one early variety. Mid-season and late varieties do better in a deep storage tote, which holds more solution.
Can I use a white bucket?
Yes, if you block the light. Paint it, wrap it in foil tape or black plastic, or stand it inside a dark bucket.
How many potato plants go in one container?
One. Two plants compete for the same solution and the same room for tubers, and the solution runs low twice as fast.
Can I use a picnic cooler as a Kratky container?
Yes, if it's watertight and the lid can take a basket. A cooler is opaque and insulated, which helps keep the root zone cool. Check that the plastic inside is food-safe.
Does a Kratky container need drainage holes?
No. A Kratky container must be watertight. The only opening is the hole in the lid for the basket.
Related Kratky potato guides
More on growing potatoes with the Kratky method, from the first sprout to the harvest.