Beat the Heat

Hot enough for you? This is the perennial question that millions of Minnesotans seed their greetings with every year late in the month of July. Just like clockwork hardy northerners get to experience a touch of the tropics from the middle of July through the middle of August when the temperatures and humidity levels soar into the 90’s. It is at this sweltering time of year when many of the fruits of our gardening labors begin to pay off, and the legacy of our gardening mistakes are made clear. Fresh tomatoes, summer squash, and visiting Monarch butterflies are among the riches being touted in some of my friends gardens while other friends of mine it would seem have nothing to talk about but the terrible heat and drought. Why are some of us enjoying the heat like a party in a sauna, while others treat this weather as though it were a plague? Do the gods just like some of us better? Or do we have any say in the outcome of this gardening riddle?In this months newsletter we’ll explore a few ways to “beat the heat”, and along the way we’ll see if we can turn one man’s plague into another man’s party.

Gardens That Withstand Drought

Water! Water! Water! This is the chant I can almost hear echoed off each patch of dry dieing lawn that I pass at this time of year.  Lawn grass is the most intensively irrigated crop in the United. States.  That’s right; our simple green lawns require more water to stay alive than any other crop grown here today, and why is that?  Simply put, grass leads a shallow life.  Turf grass will only grow roots 8 to 10 inches deep in ideal soil conditions, and usually we’re working with highly compacted soils in our newly constructed urban lots which allows for even less root depth.  Since turf grass will only grow roots a few inches deep the moisture that falls on the grass can only penetrate the soil this few inches.  The short lawn grass fails to provide any canopy for itself so when the sun shines down moisture trapped in the top of the soil is evaporated out quickly.  I’m bothering to mention all of this about the shortcomings of turf grass so that we can have a good example of what to avoid when planning a drought tolerant garden.            Logic would follow that if shallow roots, compacted soil, and poor plant choice lead to an over consumption of water, then deep roots, loose soil, and a wise plant selection should lead us back toward a garden that can withstand a drought.

As with many gardening riddles, the answer to ours is largely involving compost.  Whenever I find that the soil I’m working with is compacted so that roots and water can’t penetrate it easily I will spread out a layer of compost 4 to 6 inches deep.  Then I will turn the compost into the soil with a wide tined garden fork.  My garden fork allows me to break the soil up while leaving it in large enough chunks so that re-compaction doesn’t occur as it would if I were to break the soil up into smaller particles.  When the soil and compost are mixed in this manner water penetrates evenly and deeply thus allowing my plants roots to easily grow.  After the soil and compost are turned together I will again cover the entire garden with 2 to 3 inches of compost.  This top layer of  compost acts as a summer mulch that helps to retain moisture as it provides essential microbes and nutrients for the plants that it surrounds.  If you’re soil is very sandy you may want to attempt to add clay soil to your earth.  Clumps of clay soil spread throughout the garden will dissolve into your sandy soil over time and help with water retention.

Just as dazzling stage light will illuminate any particular performers strengths and weaknesses so does the sunlight brighten up our garden stage to highlight the talents and failings of the actors therein.  We want to make sure here that our “stage” is staffed with the appropriate “actors”, each one chosen to best perform in their distinct role.  As we learned with grass we don’t want to have the sunlight shining so close to the ground over large areas.  Creating different layers of canopy in your yard by planting trees, large and small shrubs and then perennials of various sizes will help ensure that the sunlight is not baking any one area of ground at the same time that it naturally invites wild birds and insects.  Native plants are often stars of the garden stage in the summer heat.  Plants that are originally from this region are as hardy as you can find, and will often be more adept at dealing with heat and lack of rain than their cultivar cousins.  Remember to plan for seasonal change when choosing your plants.  Your spring bleeding hearts and columbine will shine during act one, but come the hot sunny second act of the growing season they will need to be upstaged and rest in the shade of larger perennials.  As we already mentioned the less sunlight that is allowed to penetrate through to the ground, the more water your soil will retain.  This means that covering every part of the available earth with green will be advantageous for preserving water.  Just think of the forest or prairie everywhere that plants can possibly grow they do.  This natural model of plant co-operation is ours to borrow from freely.  Finally make sure to employ the help of a plant talent agency or two.  When choosing your plant pallet check with the staff of your local nursery to see what selections they can recommend for drought tolerance.  Any good nursery or garden store will have at least one staff member who can confidently answer this inquiry.  If you get a blank look from your helper at the garden store you can safely assume that they don’t know what they’re doing, and the “talent” at their “agency” is probably not in the best of spirits.

A first-rate garden performance requires a respectable earthen stage.  Work with your soil and compost in order to create a theatre worthy of an astounding performance.  Keep yourself and the rest of the audience entertained by inviting only the best performers onstage.  Timing is everything, so let each plant play its own seasonal role, and don’t be discouraged if good help is hard to find!  Above all, always remember whether in the garden or onstage, let nature be your compass and your direction will be true.