Tips for helping your garden beat the heat.
In case you haven’t been outside lately…
It’s hot out there!
The dog days of summer usually mean hot, humid weather, but this year the dogs have been barking pretty early.
Is the heat this year due to climate change? Probably not. We get these hot, dry summers every once in a while—1988, 2012, the Dust Bowl years of the 1930s—although our summers nowadays are definitely hotter than they were when I was a kid. Back then, it was unusual to have a 90-degree day in Minnesota. Today, it’s par for the course.
But hot, dry summers are something that you as a gardener will have to contend with periodically, so it’s a good idea to know how to treat your garden and yard when the weather heats up and the rain is reluctant to fall.
So here are some tips I gathered from the University of Minnesota Extension and the Minnesota State Horticultural Society, both good sources of info on how to help you and your garden survive this summer.
Drought rules
1. Plan ahead. This first tip is a little like closing the barn door after the horses are out, but it can pay to make future heat and drought part of the equation when planning your microprairie.
Here’s where prairie plants and many other natives have a built-in advantage. They’re adapted to your location, and because their deep root systems, prairie plants tend to be better able to handle low-water situations. But pay attention to new transplants, and give them more water those first couple years, especially if it’s very hot and dry.
2. Water wisely. It’s a precious resource, even where I live in the land of 10,000 lakes, and in a drought and/or extreme heat, there’s a right way and a wrong way to water.
- Water more often. In normal weather, the rule for gardens is to water deeper and less frequently, encouraging those roots to go deeper looking for water. You can break that rule a little now by watering more often, especially if it’s hot and windy out. Wind sucks the water right out of plants. Check the soil around your plants. If it’s dry a couple inches down, give them a good drink.
- Water in the morning, especially if you’re using a sprinkler. You’ll lose less water to evaporation in the cooler hours of the morning. You can water in the evening, too, but that’s less desirable since it can promote mold and mildew issues with your plants. If that’s the only time you can water, though, go for it.
- Use drip irrigation, i.e., soaker hoses. These are the best watering method in a drought. They drip the water in slowly, right at the ground, so you lose almost nothing to evaporation, and bees and wasps love them because it’s an easy source of water for them. Soaker hoses are low flow, so you only need to turn the water on a little bit, but then leave them on for a long time, up to several hours.
- Hand watering. Use a watering can with the volume marked so you know how much water you’re giving your plants, and try to water right at the base of the plant instead of pouring all over the top of the plant. This gets more water where it needed and reduces the risk of issues like blight, which happens when dirt splashes up on leaves.
- Soil type matters. Whether your plants are in sand or clay soil, they need about the same amount of water, but since sandy soil loses water faster, you’ll probably need to give your plants more water more often. You can water less often in clay soil, but remember that clay soil can get very hard when baked in the sun, causing the water to run right off when it hits it. Mulch helps a lot in this situation (see below) or try breaking up the soil surface around your plants or even build a little berm around your plant to make sure water stays put and soaks in instead of running off.
- More organic matter in the soil helps to hold water. Always key!
- Plants in containers need to be checked and watered daily or even twice daily if they’re in the sun. Water them well (but make sure your containers have drainage holes so you don’t drown your plants).
3. Mulch! Grass clippings, wood chips, even shredded newspapers help hold water in the soil. It also helps with runoff by slowing the water down before it hits the ground, it helps keep the temperature down, and the organic matter is great. Beware of dark/black mulch or weed barrier fabric. It just makes the ground hotter and radiates the heat back out at night.
4. Shade helps. It’s amazing how beating hot the sun can be in the middle of a July day. Rig up a little shade for your plants if they’re looking droopy in the mornings or they’re getting scorched (the leaves get brown and crispy). A cardboard box with one side cut out, some shade fabric or even an old bed sheet fastened up on a couple stakes will help, especially for new plants.
5. Wait on pruning or fertilizing. Pruning is stressful for plants even in good weather, so definitely don’t do it now when they’re already stressed. And don’t fertilize. Fertilizing signals to the plant that it’s time to grow, and that again is too much stress for an already stressed plant. Just give them water and some shade if necessary. Also, if you see some of your vegetable plants dropping blossoms when it’s extremely hot, don’t worry about it. That’s just a defense mechanism. They’ll recover when things cool down.
6. Let your lawn go brown. Mowing high will help a lot by letting your grass shade its own roots, and keep giving it that inch of water a week if you can. But if your cool season grass wants to go dormant, let it. Cool-season grass like we have in the northern half of the U.S. actively grows when the soil temperature is cooler. When the soil gets too warm, it goes dormant. Let it. But give it a good watering every couple weeks or so to keep it alive, and definitely keep watering any newly sodded or seeded areas. New grass is very vulnerable to heat and needs a light watering at least once a day.
7. Don’t forget about trees! Trees are such a permanent part of the landscape that we forget that they can be damaged by drought, too. Drought might not kill a full-size tree this summer, but the damage could be done and the tree might die a few years later, never quite recovering. Watch the tops of your trees to see if the ends of the branches are losing leaves. If they are, water that tree! You can use a soaker hose wrapped around the drip line of the tree or you can even just set your hose near the trunk and let it run at a slow drip or tiny stream for several hours. And if your tree was planted within the last three years, do this regularly. New trees are at real risk in hot, dry weather.
8. Finally, take care of yourself! You can’t help anyone or anything if you get sick yourself from the heat. Be sure to drink lots of water (pop and energy drinks don’t count). Stay out of the direct sun in the middle of the day and afternoon if you can help it. If you start to feel sick, faint or dizzy, your ears start ringing or your heart starts racing, get into air conditioning immediately and drink lots of water.
Hot, dry summers like the summer of 2021 are tough for gardeners, and there may be some casualties in your garden. But if you keep these tips in mind, you and your microprairie should come out the other side ready for a nice fall and a better summer next year.
Any questions?