Grow Spaces
Kratky in a Greenhouse
A greenhouse adds light and stretches the season, but it also amplifies heat in summer and cold in winter. Kratky containers need protecting from both.
What a Greenhouse Changes
Inside a greenhouse, plants get bright light and shelter from wind and rain, which solves most of the outdoor problems. In exchange, temperatures swing much more than in a house, and a container of still water feels every swing.
Summer Heat
Greenhouses heat up fast on sunny days. Warm nutrient solution holds less oxygen and invites root rot. To keep containers cooler:
- Ventilate: open vents and doors on warm days.
- Use shade cloth over the roof in the hottest months.
- Keep containers on the floor or under benches, out of direct sun, and use larger containers that warm more slowly.
Winter Cold
An unheated greenhouse can still drop below freezing on clear nights. Frozen solution can crack containers and kill roots. Move containers off cold floors, group them together, and grow cold-tolerant greens in the cool season.
What Grows Well
- Cool season: lettuce and other leafy greens, many herbs.
- Warm season: larger plants such as cucumbers, tomatoes and peppers, in large containers with plenty of solution. These drink a lot, so expect to add solution part-way through.
Humidity and Pests
Greenhouses get humid, which favors mold on leaves and algae anywhere light touches water. Keep containers opaque, space plants for airflow, and seal gaps around net cups so insects can't reach the solution.
Greenhouse Checklist
- Vents open and shade cloth ready for summer
- Containers shaded and off cold floors
- Crops matched to the season
- Large containers for large plants
