Osmocote Advertisement

Tool Time


If you grow vegetables, one of the most valuable tools around is a soil thermometer. That’s because many vegetable seeds germinate and grow even when the soil is only 45 degrees. On April 6, I took my trusty soil thermometer and discovered that the top three inches of soil where I grow annual herbs was still only 41 degrees. I waited two weeks and it gradually warmed up so I could sow spinach, lettuce, onions and Swiss chard without having the seeds rot in the cold, wet soil.

Here are soil temperature ranges for seedling development. Sowing seeds of some warm-loving vegetables (like beans) before the soil is adequately warmed, is sure to make them rot before they get a chance to sprout. And warm-loving veggies (marked with an asterisk below) should not be sown outdoors before May 15—the average last day when a spring frost could settle in the Chicago area). Otherwise, the seeds may sprout, but the tender green growth is vulnerable to a cold snap and the plant won’t survive. You can start planting these edibles once the soil reaches these temperature ranges:

Snap beans* 65-80 Beets 50-80 Cabbage 50-80
Lima beans* 75-80 Squash 70-85 Turnip 70-85
Parsley* 60-85 Peas 50-80 Radish 50-70
Lettuce 45-70 Chard 50-80 Spinach 45-65
Pumpkin* 70-85 Onion 45-75

You don’t need an expensive digital thermometer. You can get one for about $15 and it will last a long time. Check your local garden center or visit Johnny’s Seeds catalog for a complete description of the optimal soil temperatures for sowing vegetable seeds outdoors. Happy Sowing…

categories

Espoma Advertisement

popular

Article Thumbnail
Departments
From the Editor - JulyAug 2016

Seen any good movies lately? One to put at the top of your list is “Greenfingers,” whose title is the English term for having …


Article Thumbnail
Blog
A Blast from the Past

Back in January 1906, the Gardener’s Monthly Magazine featured these women perusing seed catalogs and magazines.


Article Thumbnail
Blog
Bluebirds, Daffodils and Orchids, Oh My!

The weather outside is still a tad frightful, but the sunshine and the longer daylight this past week seem to have triggered ...


Article Thumbnail
Spotlights
Sunny Disposition, Shady Needs

It is always a topic of conversation: What plants work well in sun or in shade? Or both?


Article Thumbnail
Columns
Follow the Bouncing Gall

There are two kinds of bets going on among my readers. The first is whether I will follow the tried, true and now fairly ...


questions

I have two 20-year-old pine trees whose needles are turning brown on the west side of the plants. On the east side I have a compost pile.

I live in the St. Charles region and my soil is mostly clay. What is causing the browning? Should I get rid of the compost? How do I correct the damage?

Would it help to apply a starter fertilizer on a poor green lawn in December? Will it give it a head start for spring? It hasn’t been reseeded.

What is the best time to plant a tree in northern Illinois?

ChicagolandGardening Advertisement