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What to Plant: Know Your Personnel

This blog post is written by Growing Solutions Farm lead grower, Tucker Kelly.

KYP. It means ‘know your personnel’. You hear it all the time from basketball scouts, and it refers to knowing what you’re getting or being familiar with the qualities of each individual player.

The same applies to selecting plants for your garden. KYP, or ‘know your plants’ and their qualities so you can select what works for your environment.

Climate is king

Commonly-grown crops include salad greens, cooking greens, root crops, fruiting crops, grains, and ornamental flowers. Some are members of a single category while, others are dynamic, occupying multiple categories. Some are annual, others are perennial. Some self-seed year after year, while others need to be planted in successions two to three times per year. All these qualities are things you need to know when selecting what to grow.

You can start by picking your favorite crops and varieties, learning about their qualities, and then checking them against what is possible in your climate to make sure they will thrive where you live. Do this planning early in the year ahead of spring.

Climate is perhaps the single biggest factor when deciding what to grow. Can the plant you like even grow where you live?

We use zones to describe climate qualities found across the United States. Knowing your zone is crucial for knowing what can and can’t grow in your region. The U.S. Department of Agriculture determines these zones and puts together what is called the Plant Hardiness Zone Map. Zones range from 1 in parts of Alaska to 11 in Hawaii. Each numerical zone has subzones denoted by a or b.

From the USDA Website:

“The USDA Plant Hardiness Zone Map is the standard by which gardeners and growers can determine which plants are most likely to thrive at a location. The map is based on the average annual minimum winter temperature, divided into 10-degree F zones.”

Chicago hovers around 6 a/b defined by an annual average low of -10 degrees F. Interestingly, Cook County, which is zone 6 is surrounded by a region of zone 5. Chicago’s hardiness zone ends just short of I-294 to the west, Calumet City on the south and Northbrook to the north. Zones can vary widely in small areas and are influenced by all sorts of things including proximity to Lake Michigan (or another large body of water) local topography, prevailing winds and more.

The values that define zones are based on the coldest temperatures a plant will experience during the year. They are an indicator of what will survive in a given climate and what will not.

A companion map, the Plant Heat Zone Map, was created by the American Horticultural Society to track the number of days a given area spends above 86 degrees F. While not backed by the USDA, it can be useful when determining crop availability through the hottest months. In all other cases, however, refer to the hardiness map.

Take hibiscus for example when considering hardiness. It is a beautiful plant recognized for its braided trunk, beautiful textile-like flowers, and its nocturnally-drooping drooping leaves that make it appear to sleep. It is beloved by gardeners in the Midwest, but it is a plant native to tropical environments and suited for zone 8 and will die when Chicago’s fall nights get below 50 degrees. Gardeners in the Midwest have found a creative workaround in lieu of letting their hibiscus die every October: keep it in a pot, move it indoors every fall and set it back outside in the spring.

Let’s get growing

When selecting crops, growing information should be available either on the back of the seed packet, from the distributor, and of course, online. Information on hardiness, optimal germination, planting geometry (depth, space between plants, space between rows), daily sunlight and watering needs, and more will be included.

A few constants ring true across all common food crops: they enjoy sunlight, nutrient-rich soil, moisture, and close to neutral pH. Sure, there may be some variation, but gardens and farms are not laboratories – if you can generally check these boxes, you’re in good shape. Even an alkaline soil-loving plant like kale will be successful if you can supply those general amenities, despite its pH preference.


Let’s look at tomatoes as an example. Tomatoes are vines native to Central America known for the breadth of their sweet and savory fruits of all sizes and colors. They thrive in the jungle, relishing heat and humidity, but have been transported to other regions of the world. Today, there are estimated to be more than 10,000 varieties with many more undocumented.

Those 10,000+ varieties can be categorized a number of ways, but perhaps the most significant is whether it is a modern cultivar or an heirloom. Modern cultivars and hybrids are dynamic. They are successful in fields, and hoop houses and greenhouses. They are far less susceptible to disease and pests than heirloom varieties. Their fruiting is predictable and uniform in size, shape and flavor. Their heirloom counterparts are far more genetically varied, and thus less disease-resistant or consistent in fruiting. Heirlooms, however, remain popular at farmer’s markets and are coveted for their superior flavor.

When selecting, we have to start somewhere, so let’s start at the beginning: flavor and aroma. Flavor and aroma vary widely between and could be important to you depending on what you’ll be using your tomatoes for: sauces, snacks, salads, etc. San Marzano, Roma and closely related plum tomatoes are often selected for their meaty fruit and their adaptability to sauces. Sun Gold and the myriad red cherry tomato varieties are commonly eaten right off the vine or dropped into salads. A number of tomatoes found in the grocery stores and heirloom beefsteak tomatoes make excellent slicers for sandwiches. We like what we like, and what we like we should grow.

Generally, all varieties love sun, high-nutrient soil, and close to neutral pH. Tomatoes love moisture, though they do not love overly wet soil. For all tomatoes, especially those that grow to be 15 to 20 feet, moisture must also be present in the air.

Next, consider the space you have to work with. If trellising a 15- to 20-foot tall vine is not possible, you should avoid selecting a variety that is indeterminate, meaning it will grow indefinitely until cold weather kills the plant. Given limited vertical space, selecting a bushing variety is best. A trellis or cage will work in this situation.

Assume that we’ve selected an heirloom bush variety, we have the correct nutritional needs in our soil, and the plant is bearing fruit. Heirlooms bush vigorously, producing a lot of foliage. While the foliage encourages photosynthesis, it can inhibit flowering, fruit production, and fruit size. Prune all suckers, branches growing at a 45-degree angle between the stem and branch. You can prune with either your hands or pruners, but, whichever you use, make sure that they are clean. Using unsanitary equipment on plants may cause disease.

We know what we’re growing, so we know that tomatoes are annual in Chicago’s plant hardiness zone. They will produce enough fruit for you and your neighbor through September, slow in production through October, and wilt by November. They are, after all, tropical jungle vines, but we already knew that. KYP!

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