Cool Season Crops
Grow cool season crops like lettuce, broccoli, and potatoes to get an early start on your spring garden. These crops thrive in cooler temperatures and are ideal spring plants. Knowing what to grow, when to plant the seeds, along with a few tricks, will help ensure your spring vegetables and crops thrive.
Know What to Grow
Many crops can tolerate colder weather and soil and can be planted as early spring vegetables. These plants are labeled as cool-season crops. Unlike warm-season crops, cool-season crops should be planted so that they mature when the weather is still cool and before the summer heat hits. When warm weather arrives, many of these early crops tend to “bolt” or prematurely run to seed. These crops flourish in temperatures lower than 70 degrees Fahrenheit so planting their seeds or transplants at the right time—ideally, early spring—will help ensure a healthy harvest.
Which spring garden plants you can grow (and when precisely to plant them) depends upon where you live. The USDA Plant Hardiness Zone Map - based on the average annual minimum winter temperature, divided into 10-degree Fahrenheit zones - offers expert guidance on which plants are likely to thrive in a given location.
Hardy and Semi-Hardy Crops
Cool-season crops can be planted when the soil and air temperatures are at least 40 degrees Fahrenheit. These crops are often further divided into hardy and semi-hardy categories, depending upon their ability to withstand cold temperatures.
Hardy vegetables tolerate cold temperatures the best—their seeds will germinate in cool soil, and seedlings can typically survive heavy frost. Plant these seeds or transplants two to three weeks before the date of the average last spring frost; they will grow in daytime temperatures as low as 40 degrees Fahrenheit.
Semi-hardy vegetables withstand light frost. These crops grow best when the minimum daytime temperature is between 40 and 50 degrees Fahrenheit and can be sown as early as two weeks before the average last spring frost.
Some cool season crops fare better when direct seeded, while others can be started indoors. This chart outlines recommendations for popular crops:
Spring Garden Plants: Tips for Success
Gauge soil temperature: The odds of successfully growing cool-season crops increase if you plant them at the right temperatures so check your soil temperature before beginning. When planting seeds or transplants, measure the temperature at the recommended planting depth. Soil thermometers are available at most garden shops, but almost any thermometer will do, as long as it measures temperatures down to freezing.
Expect the unexpected: An unexpected hard freeze can ruin young plants. Keep floating row covers or old sheets on hand to cover plants and provide necessary warmth just in case temperatures dip below cold-tolerance guidelines.
Spread your bets: Spring weather can be unpredictable in many regions of the country. Sow each crop in a couple batches, staggered about a week apart, to improve your odds of catching ideal growing conditions.
Double-check with the experts: Contact your local cooperative extension office to confirm which cool-season plants thrive in your area.