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

popular

Article Thumbnail
Columns
MacGregor Redux

"Hey, where's Stinky?" "Mmmphrgbl?" "Stinky!" "Phbbmmrrggnndr." "Didn't your mama ever teach you not to talk with your mouth ...


Article Thumbnail
Columns
Behind the Curve (and losing ground)

I think I’m missing a gene. Okay, maybe two or three. This is the time of year when gardeners are told to dream, to curl up ...


Article Thumbnail
Columns
Waiting for Gardot

“Hey, Gerry.” “ Morning, Al.” “ Where’s Carey?” “ They moved him to the front this morning.” “ No kidding. Think we’re next?


Article Thumbnail
Features
Bursting Forth

Ted Nyquist’s rhododendrons light up his woodland wonderland.


Article Thumbnail
Blog
What do the bees do in October?

What do the bees do in October? If you have New England aster in your garden, they keep foraging like mad.


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?

My lilac had a grayish blight on the leaves this summer. What caused this and how can I prevent it?

I have two strawberry plants in a hanging basket in my yard. I have not had any fruit from them although the vines hang down. I give them plant food once a month and water daily. What am I doing wrong?

ChicagolandGardening Advertisement