Summer Gardening: How to Care for Plants in Heat and Humidity

May 15
3 min read

I’m an early morning person. I’m usually up around 5 something, but by the time I have my coffee, chat with my hubby and get dressed, I find I get outside between 7 – 7:30am.

As I walk around the yard, I see the dew on everything. If it is not wet from the early morning dew, it could be my irrigation which I have set to go off in the morning.

Wet Plants in the Morning

Coriander leaves covered in early morning dew — Wet Coriander

Summer gardening is all about frequent and keen checks. Seeing the wetness this morning prompted me to write this Herb Talk about how to deal with your plants when they are wet.

You want to be cautious when you water later in the day in high heat and sun, at least in zone 8 and higher. Overhead watering when the plants are hot can have an effect on the leaves, so I have found watering in the morning is best.

Watering Timing Matters

Chives wet from watering or morning moisture — Wet Chives

The only time I water in the evening is when we are having a very dry period. If you see a need for extra watering in the evening, try to get it done before it is too dark. When you water in the evening, the wetness doesn’t tend to dry at night. Not a good habit, plants too wet all night can promote disease.

Avoid Working With Wet Plants

Do not harvest or work with your plants while they are wet, from early morning dew, irrigation or rain. Wounds, even the slightest, will transfer disease into the plant.

I have to admit this is a weakness of mine. I see a problem and I immediately start to correct it. Then I feel the wetness and my brain says, “what the heck are you doing?” I realize I’m doing what I tell people not to do.

Lessons From the Greenhouse

I learned this while working in tomato research greenhouses. In the early days when there was a lot I didn’t know, (and I would work in the greenhouse early because it was cool, the greenhouses heat up fast), my supervisor walked in one day and saw what I was doing. He explained to me the issues that can happen when working with wet plants.

Heat and wetness tend to promote disease, both bacterial and fungal. So, heads up. Now in the early morning when I do my first walk around, I assess what is going on in the yard: are there pests? disease? Do I have issues that warrant spraying (which I do in the mornings before it gets too hot)? Is it time to fertilize, etc.?

Understanding Plant Wilting

Something else that would catch me off guard was seeing plants looking wilted when they shouldn’t. In the hydroponic greenhouses wilting would alert me to possible irrigation problems. I later realized that it doesn’t have to be an irrigation problem for the plants to wilt. It may have to do with having cloudy days and then a sunny day with high heat.

Recently I noticed at midday a pepper plant in my garden looking wilted and the leaves even had a slightly gray look, not lush green like normal. The ground was moist, so that was not the problem. This just doesn’t happen to peppers and tomatoes, like I have seen on other crops.

Wilting Lavender

Lavender plant showing signs of wilting in heat — Wilting Lavender

I also noticed a lavender plant that had flowers starting to sprout blooms. The tall stem with the flower bud was drooping. There was no issue of dry media. I realized that this plant was in a shadier location in the morning that became sunny. When I moved it to a sunnier location starting in the morning and filtered light in the afternoon, it corrected the problem.

Why Plants Wilt in Heat

So, look for the appearance of wilting, always check for moisture, that your media (dirt around the plant) is not dry. It is a shock of sorts the plant goes through with the change in temperatures and sun.

There is not much you can do except allow the plants to harden off. The plants will get past that phase and perk up again. The only other option is to move the plant where it gets sun in the morning and some shade in the afternoon.