The Q&A Archives: Hot, Dry Desert Heat/Container Plants

Question: This is my first time trying to grow tomatoes and green peppers in containers. I used miracle grow potting mix (organic) How do you get enough sunlight to these plants without burning the leaves when the temperatures during summer range between 95-110 degrees. My tomatoe plants have leaves that are yellowing on edges, and my pepper plant leaves are curling and becoming brittle. The new growth of leaves on both plant seem to be nice and green. Any solutions or help would be great.

Answer: When did you transplant your tomatoes and peppers? Here in the low desert, we have two distinct growing seasons, with different plants thriving in each. The cool planting season starts around late September/October with plants growing through April/May. The warm season planting starts in Feb/March and plants go until the heat hits, or some live through the summer. Tomatoes and peppers are considered warm season plants and they are best transplanted from mid-Feb. to mid-March. This allows them to develop root systems, grow, and flower and set fruit before the heat. Tomato pollen isn't viable much over 90 degrees, so the plants won't set fruit now. Some gardeners harvest and let the plants die, rather than try to keep them alive through the summer. Other gardeners make the effort, hoping the plants will set more fruit in the fall. Container plants have it rough because the soil temperatures heat up considerably more than the outside temperature, and the roots have nowhere to "hide." Here are a few suggestions: you can put the containers in a northern or eastern exposure where they receive morning sun, but are protected from hot afternoon sun. Put several inches of mulch on top of the soil to retain moisture and reduce temperatures. Put the container inside another larger container and stuff newspaper or packing chips in between the two; the sun hits the outside container and the inside container has a bit of a buffer/insulator. If that isn't feasible, erect a cardboard "collar" around the container, which will also act as a buffer. Keep containers out of windy conditions; wind is extremely drying to the plant foliage. Keep the soil moist. If a container does dry out, it's hard to remoisten the soil completely. If the container is small enough, plunge it into a bucket of water until it soaks up the moisture and the soil is rehydrated, or set it on a deep saucer. Yellowing edges can be a sign of salt burn. Salts in the water and in fertilizer build up over time. Browning usually occurs on the old leaves first. This excess salt accumulates in the leaf edges, where it kills the tissue and the leaf dries out and turns brown. It's important to water deeply and slowly. At least once a month, water deeply enough to "leach" or push salts well below the root zone. Frequent, light "sprinklings" allow salts to accumulate in the top layers of soil, where the roots are, which is bad news. Similar symptoms occur when too much fertilizer has been applied. Always water plants thoroughly before and after applying fertilizer to help prevent burn. Also, if plants are in too much direct sunlight, foliage can yellow and then turn brown, as it is basically "burning." I hope this info helps!

« Click to go to the homepage

» Ask a question of your own

Q&A Library Searching Tips

  • When singular and plural spellings differ, as in peony and peonies, try both.
  • Search terms are not case sensitive.

Today's site banner is by dirtdorphins and is called "sunset on summer"