Gardening: Mother Nature and the right tools are your planting guides

Nancy Szerlag
Special to The Detroit News

In spring, when buying trees and shrubs, I recommend you take your cues  from Mother Nature.

When shopping a big box for groceries or hardware, I often case the garden section in search of a treasure. You may find interesting plants that growers included in a shipment that were overages from other orders or test plants.  But what I see more often in early spring are trees or shrubs for sale totally leafed out when those in my neighborhood are bare or just beginning to bud up.

In early May in Michigan, trees and shrubs sold in these outlets are often shipped from warmer climates. They may be selling at a discounted priced, but if they are fully leafed out and those in your neighbor have yet to flower or leaf, they may be no bargain. Plant them in the next couple of weeks and a late season frost will turn those leaves to toast.

Flowers need the right planting conditions.

After having spent several weeks sheltering in place as a single, last weekend I put on my mask and traveled out to a greenhouse. I would not have gone, but I was on a mission – in search of a hard-to-find tomato variety – and I was pretty sure this garden center grew it.  

The place was mobbed, and carts were filled with tender flowering annuals fresh out of greenhouses. I wanted to get a megaphone and scream out – it’s way too early to buy these plants unless you are willing to drag them indoors every night for the next couple of weeks!

A couple of tools that will help take the mystery out of when to plant outdoors are various thermometers. A soil thermometer, available at big boxes and garden centers, will tell you when the soil has warmed enough to safely plant. Temperatures vary from plant to plant.  They will also help you identify microclimates in your landscape.

Another useful tool that tells you what’s going on in your patch is a maximum /minimum thermometer – it registers the high and low ambient temperatures in a 24-hour period and will help you figure out what and when to plant in different parts of your landscape. Available at most big boxes and hardware stores, they are relatively inexpensive.

My little tomato plants are heat lovers, so they will be living under a grow light in the warmth of my office where they will stay until my “tools” tell me it’s time to harden them off and plant them outdoors, probably around Memorial Day.

 Nancy Szerlag is a master gardener and a Metro Detroit freelance writer. Her column appears Fridays in Homestyle. To ask her a question go to and click on Ask Nancy. You can also read her previous columns at