Greenhouse Shade Cloth Calculator
Find the right shade cloth percentage for your plants and climate, and the cloth size for your greenhouse.
How it works
What shade cloth percentage should I use?
The percentage is how much sunlight the cloth blocks. Most food crops need lots of light, so they do best under light shade. Shade-loving plants and people are happier under heavier shade. In hot, sunny climates, go 10 to 20% heavier.
| Plants | Shade |
|---|---|
| Tomatoes, peppers, cucumbers and other fruiting vegetables | 30 to 40% |
| Herbs, flowers and mixed plants | 40 to 50% |
| Lettuce and leafy greens in summer, seedlings, cuttings | 50% |
| Orchids, ferns, begonias and other shade lovers | 60 to 70% |
| People, sitting areas and garden rooms | 70 to 80% |
Sizing: exterior shade cloth goes over the roof from eave to eave, plus about a foot past each end. We measure the roof over the curve or the peak, not straight across.
Questions
Greenhouse shade cloth FAQ
What percentage shade cloth is best for a greenhouse?
For a mixed vegetable greenhouse, 30 to 40% is best. Use 50% for leafy greens and seedlings in summer, 60 to 70% for orchids and shade plants, and go heavier in very hot climates.
Is shade cloth better inside or outside a greenhouse?
Outside is better for cooling, because it stops the sun before it heats the glazing. Inside shades are easier to open and close and protect from wind, which is why many glass greenhouses use interior shade curtains.
When should I put shade cloth on my greenhouse?
Usually from late spring, when days regularly pass 80°F, until early fall. In hot southern climates you may need it from March to October.
Does shade cloth keep a greenhouse cooler?
Yes. A 40 to 50% shade cloth can lower the temperature inside by 10°F or more on a sunny day. It works best together with roof vents or an exhaust fan.
More tools
Other greenhouse calculators
- Heater Size CalculatorHow many BTUs it takes to keep your greenhouse warm on the coldest night.
- Heating Cost CalculatorWhat a winter of heating will cost with electric, propane or natural gas.
- Fan and Ventilation CalculatorThe exhaust fan CFM and vent openings that keep summer heat down.
- Snow Load CalculatorHow much the snow on your roof weighs and when to brush it off.
- Foundation CalculatorConcrete, gravel, pavers and lumber for your greenhouse base.
- Greenhouse Size CalculatorHow big a greenhouse you need for the plants you want to grow.
- Grow Light CalculatorHow many grow lights it takes to give your plants enough light in winter.
- Rainwater CalculatorHow much water your greenhouse roof can collect for your plants.
Want a second opinion?
Tell us about your greenhouse and where you live, and we will help you get it right.
Call 678-408-8222Send us a message