Kratky Strawberry FAQ
Short answers to the questions people ask most about growing strawberries with the Kratky method of hydroponics.
Kratky Strawberry Questions and Answers
Each answer is brief on purpose. If yours is not here, send it to us through the contact page.
What is the Kratky method?
The Kratky method is a passive form of hydroponics. A plant sits in a net cup above a container of nutrient solution. As the roots take up the solution, the level drops and leaves an air gap that supplies oxygen to the roots. There is no pump, no air stone and no electricity. See the Kratky method guide.
Can you grow strawberries with the Kratky method?
Yes. Strawberries are more demanding than lettuce because they live longer and carry fruit, so they need a larger container, regular checks on the solution and top-ups through the season. See the setup guide.
What container is best for Kratky strawberries?
Use a dark, opaque container with a lid that holds the net cup firmly. Light reaching the solution causes algae. Bigger is better for strawberries, because a larger reservoir keeps nutrient strength and pH steadier between top-ups. See the containers guide.
How much light do Kratky strawberries need?
Outdoors or in a window, aim for 6 to 8 hours of direct sun a day. Under grow lights, which are weaker than sunlight, plan on 12 to 16 hours a day. See the lighting guide.
What pH should the nutrient solution be?
Keep the solution between pH 5.5 and 6.5. Check it regularly, not only when you mix it, because the pH drifts as the plant feeds. See the pH guide.
How often should I change or top up the nutrient solution?
Top up whenever the level gets low, and always leave an air gap so part of the root mass hangs in air. Many growers replace the solution completely every few weeks, and sooner if it turns cloudy or smells. See the nutrients guide.
What temperature is best for Kratky strawberries?
Strawberries grow and set fruit best between about 60 and 80°F (15 to 27°C). Hot rooms reduce flowering in many varieties.
Can I grow Kratky strawberries indoors?
Yes. Indoors you need to supply enough light, keep the room in a comfortable temperature range and pollinate the flowers yourself.
Do I need to pollinate strawberry flowers by hand?
Indoors, yes, because there are no bees or wind to do it. Brush the center of each open flower with a small soft brush, or gently shake the plant, every day or two while it is flowering. See the pollination guide.
Which strawberry varieties work best?
Day-neutral and everbearing varieties are the usual choice because they fruit repeatedly. See our strawberry varieties page for a comparison.
How do I prevent algae and mold?
Algae grows where light reaches the solution, so use an opaque container and cover any openings. Mold on leaves or fruit comes from still, humid air, so give the plants airflow and remove affected parts promptly. See the problems guide.
What pests affect Kratky strawberries?
Aphids, spider mites and whiteflies are the most common. Inspect the undersides of leaves often and treat early, for example with insecticidal soap.
What are the signs of a nutrient problem?
Yellowing leaves, slow growth and poor fruit are the usual signs. Check the pH first, since a pH outside the 5.5 to 6.5 range stops the plant taking up nutrients that are already in the solution. See the problems guide.
