In the spring, we’re always eager to get our seeds and plants in the ground as soon as possible. But when, exactly, to plant them? Some, like radishes and carrots, like cool conditions and won’t germinate if it’s too hot Others, like beans and squashes, won’t germinate unless the soil is nice and warm.
But springs — especially in Iowa — can vary radically. What to plant when?
Local legend helps us a little. There’s an old saying that you should plant potatoes on St. Patrick’s Day. Another especially wonderful tale is that farmers know when to plant corn by sitting on the ground on their bare bottoms and if it’s comfortable, it’s time to plant.
Fortunately, you can figure out if the conditions are right for planting seeds with a much more conventional (and modest) method — by taking the temperature of your soil. It takes just minutes.
The ideal tool is a soil thermometer. You can find one in most better-stocked garden centers or online, for about $20. But just about any thermometer that will register between 40 and 100 will do. This includes most food thermometers. (Just be sure to wash them well after use, of course.)
See the attached chart of the most commonly planted vegetable seedlings and flowers. Plants that are commonly started as seedlings outdoors, such as tomatoes or peppers, are not included.
Join our mailing list to get weekly emails with a round-up of our gardening coverage straight to your inbox.
• Make sure the soil is weed- and grass-free, and has been well worked so that it’s fine and even.
ARTICLE CONTINUES BELOW ADVERTISEMENT
• Don’t work the soil when it’s too wet or too dry or it will form problematic clumps.
• Dig down at least a foot or more to loosen the soil and promote good drainage.
• Ideally, spread 1-2 inches of compost on top of the soil and then work in to fertilize the soil and improve its texture.
• Keep the seed bed evenly moist for the first week or two. This may mean watering it lightly every day or two if the weather is dry.