The Dirt on Soil Temps

Mary Reilly-Kliss Ozaukee Master Gardener

Coordinator, Washington County Community Garden, West Bend

A soil thermometer is a must-have garden tool.

Though the ambient temperatures are warming up where I live in central Washington County, the garden soil has a way to go. One of the best garden tools for this is a soil thermometer. You could use a regular food thermometer, but you would have to know what temperature is best for a particular seed to germinate or plant to thrive. Thus, I really like, and use, a soil thermometer. I found mine at Jung's in Randolph, Wisconsin but it is also available in a number of catalogs and in both online and brick and mortar stores.

So far, we have planted some onions (plants, not sets), lettuce and Swiss chard. This coming week (May 5) we will plant carrots, beets, more lettuce, and maybe some peas or cabbage. The beans will go in when the soil temperature is close to 70°, tomato plants near the end of May, and squash and zucchini in early to mid-June.

Another soil factor to consider is its texture or tilth. Because of the recent rain, the soil can rapidly compact if you try to plant or do too much digging. Ideally, good planting texture is like a slice of chocolate cake, crumbly and loose. If you take up a handful of soil and squish it, and it stays in a block like clay, it is too wet and will take on a cement-like texture if you dig.