Hot Weather Gardening Tips UMN extension


June 13, 2021

Drip irrigation releases water directly to the soil surface near the roots of plants.

We’ve just had a few weeks of record high temperatures in June, and meteorologists predict we’ll continue to see above-average temperatures for the rest of the summer.

What does this mean for the way we manage our gardens?

Water wisely

We’ve been in drought conditions for weeks at this point, and the wells are running out. Many cities have started implementing watering restrictions, so be sure to check your local ordinances. In many communities, this feels like watering only on certain days of the week depending on which side of the street you live in or even / odd addresses.

  • Water your plants in the morning as early as possible. This allows the soil and your plants to absorb more water because in the heat of the day there is more evaporation from the soil surface.
  • Drip irrigation is ideal because it deposits water directly on the soil surface and can be targeted.
  • Hand watering is also very effective: water as close to the soil surface as possible.
  • If you must use sprinklers, try using sprinklers that lay the water low to the ground rather than spraying high in the air to minimize evaporation.
Tomato plant with a lot of leaves that has not been pruned.
Wait to cut the tomatoes until the heat wave passes so that they are less stressed.

How much water do you need?

The average vegetable garden needs about 1 inch of rain per week. This looks like :

  • 62 gallons for an area of ​​10×10.
  • About 20 gallons for a 4×8 raised bed.

In extremely hot weather (daytime temperatures over 90 and nighttime temperatures over 70), try watering every day or every other day. In a 10 x 10 foot garden, that would mean giving your plants 8 to 9 gallons of water each day.

If you’re watering from a hose, fill a container with a known volume (like a gallon of milk or a 5-gallon bucket) and calculate how long it takes. Multiply that by the number of gallons needed to determine how long you need to leave the hose in place.

Learn more about watering wisely during drought and other difficult conditions.

Trim carefully

June is a great time to prune your tomatoes and some other plants like lilacs. However, keep in mind that when it is extremely hot outside, your plants are stressed. Pruning is another stressor, so if possible try to wait until conditions have cooled slightly before pruning your plants.

Only prune when rain is not forecast and humidity is low. This limits the risk of infection as the plants heal wounds left by pruning.

After pruning, water your plants abundantly, directly on the roots.

Grass, grass, grass!

Bean plant growing in the ground surrounded by weeds.
This bean plant competes for moisture with weeds.

While weeds also need water to grow, many common weeds are well adapted to drought conditions and the heat allows them to grow quickly. Try going out every other day in June to remove weeds from your garden, as they are easier to remove when they are small and can quickly become a lot of work to manage.

Keep in mind that weeds use precious water as well, so removing them will reduce some of the competition for your garden plants.

The right plant, in the right place

Withered ligularia plants in the foreground, surrounded by other plants that appear less stressed.
Ligularia plants thrive in humid conditions but do not thrive in this dry rain garden.

Droughts give us a glimpse of plants that may not be quite suited to our landscapes. Take a look at your garden, are there any plants that are much more wilted than others, or plants that you water every day to stay alive? Maybe this particular plant isn’t well suited to your landscape or that particular location.

If certain types of plants are thriving, consider removing the plants that are not doing well and replacing them with plants that are.

As you do this, study the soil in the area. You might have a low spot that you think would make a good rain garden, but one side of it has much sandier soil than the rest, causing it to drain faster.

Learn more about evaluating your site and resources for choosing the appropriate plants.

Take care

Make sure you take breaks and drink plenty of water while you garden.

Know the signs of heat stress: headaches, nausea, dizziness, weakness, irritability, thirst, heavy sweating, etc., and get help if needed.

For more information on heat-related illnesses, visit the CDC’s heat stress page.

Author: Natalie Hoidal, extension educator, local foods and market gardening


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