Cool season veggies like spinach, lettuce, and radishes can be planted from seed starting about the 3rd or 4th week of March. They germinate rapidly and usually in less than one week they are above soil. The photo below shows radish seedlings one week after planting. These radishes were planted from seed on March 30, 2012.
The cool season crops are tolerant of late spring frosts so give those who are anxious a chance to get back into the soil and the garden. The photo below shows spinach seedlings (look closely) just breaking the soil surface one week after they were planted, also on March 30, 2012.
The cool season crops generally will be ready for harvest as early as 3-4 weeks after planting. They will produce until the heat of summer arrives. A second crop of cool season crops can also be planted in the fall, after the heat of summer, generally the 2nd or 3rd week of September. This fall crop can sometimes be productive into November and December.
Frost sensitive plants like tomatoes, chili, bell peppers, squash, melons, and eggplant cannot be planted until the danger of frost has passed. If planted before the last frost date you risk losing them all, even in the event of a light frost. If you have young tomato or chili plants, etc. you can now begin to acclimate them to outdoor conditions. Place them outside during the day to get acclimated to the sun, wind, humidity, etc. and move them indoors or to a sheltered area at night. Watch the weather for your area and if there is no danger of frost you could even leave them outdoors overnight, but keep your eye on the weather as a late spring frost can kill them all one chilly night or morning.
For more information about what to plant and when to plant contact the nursery at firstname.lastname@example.org or come by the store. We have starter plants available now for your garden.
Staff Plant Physiologist