Baby cucumber
Soil temperature—not the calendar—is the real signal for when seeds will sprout. Soil warms up far more slowly than the air. Many garden crops can be direct-sown this month when your soil is sufficiently warm to support germination and ensure survival of tender seedlings.
Prominent among these are all the vegetables in the group known as Cucurbits, including cucumbers, melons, summer and winter squashes, pumpkins and gourds.
In addition, beans need warm soil to germinate. In cold soil, their seeds are likely to rot. White-seeded bean varieties can handle slightly cooler soil than those with darker seeds. Sweet Corn needs warm soil, too. Basil is easy from seed in warm soil. We highly recommend using a Soil Thermometer to measure soil temperature. And we have some in stock!
There are lots of flowers you can still direct sow in your garden, such as Zinnia, Mexican Sunflower (Tithonia), Amaranth, Calendula, Marigold, Morning Glory, Hyacinth Bean, Scarlet Runner Bean, Nasturtium, Sweet Alyssum, Moss Rose (Portulaca), Black-eyed Susan, and Sunflower. We recommend covering your seeded area or row(s) with our ‘Seed Guard’ row cover cloth to protect seeds from disturbance by critters or heavy rain.
Minimum Soil Temperatures for Sowing Summer Vegetable Crops
Basil – 65 F
Beans – 70 F
Sweet Corn – 60 F
Okra – 75 F
Melon – 70 F
Squash, Pumpkin – 65 F
Cucumber – 60 F