Protect Your Veggie Garden from Harsh Heat

June 7, 2010
Holly Deyo

This is definitely an ugly start to the week! Since weather these days is so unpredictable with wide temperature swings, blast furnace heat in some areas to freak frost in Montana last week, and unforgiving tirades of hail and high winds in between, gardens need protection.

You know it's going to be a miserably hot day in Colorado when the thermometer already reads 70ºF at 4 a.m. This is just nasty when there's still 2 weeks left of spring. Today we have one of the worst weather combinations – very hot temperatures accompanied by high wind. This can give plants heat shock, leaving them depleted of strength and gasping for air.


Photo: Anaheim pepper hammered by hail left holes in the leaves and shredded some from their branches last week. This pepper obviously has a will to live. Even though the plant was fairly well battered, its flowers (circled in red) still clung to the plant.

Photo: Hail punctured these squash leaves though the plant is already growing new ones. A few others weren't as lucky and were sawed off at ground level. Weather forecasters said there was only a 20% chance of rain and no mention of hail threat. Ah! What do they know!

Last week brought an unexpected pounding from penny-size hail. Ice balls even that small ripped "arms" off tomato plants, shredded tender pepper plant leaves and "aerated" squash leaves. Amazingly the peppers and tomatoes weren't hurt, but the plants themselves suffered. I was literally one day late adding protection to the fruit and veggie beds – something that was planned for the next day's high heat.

Yes, plants can get "heatstroke"

Giving plants shade protection is easy to do. Since the brunt of the sun's rays comes directly overhead and from the west, we draped 30% SunBlocker fabric over the tops and down the western side of the garden boxes. This lets them enjoy the early day sun and shades them from brutal late day rays. 30% is just the right density to allow rain and water flow through, but gives plants protection from hail, wind and heat.

Since our raised beds are already surrounded by
½" hardware cloth for rodent and bird protection, slipping SunBlocker cloth into place takes about 5 minutes, if not less. It's secured with wooden clothespins clipped to the hardware cloth. Nothing fancy.

Photo: Before adding Sunblocker fabric: Besides the container plants, some of these tomatoes and peppers were also hit by hail. Since the storm came from the east, raised beds in back of the house fared well. Containers pots on the driveway paid a price.

Photo: Lettuce, spinach, tomatoes and peppers hide from the heat under 30% SunBlocker fabric. It works great as hail and wind protection, too. Of the other raised beds not pictured, some sport shade cloth, some don't.

Side note: We've found it easier to keep beds free from grass by removing most of the vegetation around the raised beds. Because there is so much wind in this area, native grass finds a happy home in the rich Super Soil. It may not be pretty, but it saves weeding time.

TIP: Wood clothespins are a better a choice than plastic ones since plastic eventually crumbles under the UV assault.

If your garden doesn't have hardware cloth in place, use wooden dowels, T-posts, broomsticks, long sticks, trellises – anything you can tap into the ground that supports the shade material.

SunBlocker and sunshade fabric are not usually found at home improvement chains or garden centers. Why? I have no clue, but it can be ordered online. One place to purchase it is Farmtek. Garden Gold lists other suppliers if you don't find it locally.

TIP 2: Water plants early and thoroughly before the Sun becomes brutal. Plants will be better equipped to deal with heat by absorbing needed moisture and less water will be burned off through evaporation.

Container Plants

On a different note, Stan and I decided we are done with store bought tomatoes so we planted a number of tomato and pepper varieties in easy-to-move containers. Half are on the back deck and some were on a driveway (pictured below). This fall, when frost nips at our fingers, we can still reach out and pluck homegrown veggies off the vine. By moving these planted pots into the house and adding grow lights, veggies keep producing year round. Good-bye crummy carboard-tasting store bought 'maters!

Photo: Earlier this spring container pots holding tomatoes and peppers sat on concrete. Warmth from the driveway during the day kept them warm at night. On evenings when it dipped into the 30's, it was easy to whisk them into the garage so they didn't freeze. Not only do container pots free up raised bed space, this winter they'll find a nice home inside.

Photo: Unfortunately tomato and pepper plants were hit by last week's hail. One chile plant folded up his tent, said "this is too hard" and died. Leaf damage is visible and some of the stalks are bare of leaves. Amazingly all of the fruit and flowers stayed superglued to the plants. Taco's thinking, "Forget the plants, Mom, and walk us before it gets too hot!"

Photo: Arranging pots on a driveway can add color and interest to a yard while taking up only a little space. Now that it's going to be miserably hot today, the "driveway veggies" will be moved under the hedge shown at the left side in this image.

Photo: Pueblo chilies close to harvest hide out from the heat under a hedge.

Photo: This little patio tomato is already getting color. Later this week, it will have to go under a wire cage for protection against birds. The hedge that protects them today produces a ton of little red berries, which are candy from a bird's point of view.

Photo: More tomatoes sit beneath the hedge and on it goes in a neat protective semi-circle. These container plants wished they could have been sitting here when the hail hit!