A Matter of Degrees
Whether you’re transplanting started cucumber plantsorsowing seeds directly in the garden, your soil’s temperature is the key to success. The warmer the soil, the less time it takes for new growth or baby seedlings to appear. Use these guidelines for seed germination:
- Seeds in 80°F to 90°F (26.6°C to 32.2°C) soil take from 3 to 10 days to germinate.
- Seeds in 65°F (18.3°C) to 80°F (26.6°C to 26.6°C) soil take more 10 days to germinate.
How to Measure the Soil Temperature
An inexpensive soil thermometer from your home and garden store will remove the guesswork from knowing when to plant cucumbers. Look for a glass bulb model with a sturdy, corrosion-resistant metal probe. To take the temperature:
- Test the morning and late-afternoon temps for several consecutive days.
Loosen the soil with a screwdriver before inserting the probe to the depth recommended on your seed packet. If you’re transplanting started cukes, insert it to the depth of their pots.
- Leave the thermometer in the soil as long as the manufacturer recommends before recording the temperature. Shade the exposed portion from the sun with your hand.
- Wipe the thermometer down with a clean cloth after each reading to prolong its life.
- Wait to plant until your two daily readings consistently average above 65°F (18.3°C).
Expert gardener’s tip: Skipping the soil temperature test and simply waiting until one month after your last expected spring frost date to plant isn’t advisable. A surprise late frost can decimate baby cukes, leaving you with replanting and a delayed harvest.
Getting an Early Start on Soil Warming
Every day your soil remains too cold to plant means one fewer day your cukes can be growing. Speed the warming process with pre-planting techniques that also produce a more vigorous, flavorful harvest:
Enrich Your Soil with Organic Material
As soon as your ground is workable, improve it with plenty of organic compost and fertilizer . Because they’re darker than the soil, they’ll absorb heat more quickly. They also generate heat while breaking down into nutrients that will get your cukes off to a great start.
Use Raised Beds
Raised beds angled toward the noontime sun speed warming with faster drainage and maximum sun exposure.
Warm Your Beds with Plastic
A layer of clear or black plastic sheeting does wonders for drying out soil wet from early spring rain or melting snow, and the soil warms more quickly when it’s dry. Be sure to anchor the plastic’s edges with soil or rocks for wind protection.