How are peppers and mulch used in a desert environment?

Question

I have a couple of pepper plants that I've recently procured. Since I do not want these to go the way every other plant that has been gifted to me (i.e. death), I transplanted them into some large planters and used "moisture-control" potting soil, and applied a 3" layer of mulch to the surface. Being that I live on the surface of the sun (Phoenix, AZ), I've had to rescue my poor peppers from the sun a couple of times, despite advice that peppers love the sun. The planters were getting too hot, the moisture seemed fine, and the planters were in shade most of the time, but I could see visible signs of stress on the plants. I had to water them to cool the soil.

So what I'm asking is:

1. Should I remove some of the mulch to allow the soil to dry (recommended by people for peppers)?
2. Should I put them in an even more shaded area?
3. Should I be concerned about plant diseases germinating in such a hot and humid environment?

Answer 1

I have some suggestions:

1. plant it under shade such as tree or big leave vines. You've done this.

2. place it big tank with water next to your planter, water can absorb a lot of heat, maybe it would help.

3. Don't use plastic pot/planter. Use terracotta pottery if it's available to you. Choose a pot without varnish or shiny coating. Pottery with cracks will help release the heat. In Chinese we call it 陶盆. This is a sample picture:

The pot is light brown in colour and its surface is dull.

4. Try to put some pebbles in the base of your pot, then submerge your pot with some water in your saucer. Of course not too much water. I am trying an experiment with French Lavender with this setting. The temperature of the environment vary from 29 degree Celsius to 36 or above. They are surviving, not very good, but good.

This is my poor illustration :p

5. Install a fan.

6. splash the floor with water. It is better to have a fan together to blow the hot water vapour away.

Answer 2

Peppers do like the sun - but that is relative! Even here in North Texas, fruit will get sun scorching if unshaded, although the plant foliage does like the sun with water.

When you talk about "visible signs of stress": Do you mean the leaves go all floppy and almost 'thin' like cling-film but remain green? Then when you water them in the evening, the leaves perk up? If so, this is a normal heat/low-water response. This time of year mine do that almost every day (highs of 95-105F). Although I have fruit at the moment, my main aim during summer is to keep the plants healthy. Care more about growth and leaves rather than fruit. Then when September comes, the flowers will survive, the fruit will set, and I'll have a bumper crop through to the first frost.

Your mulch sounds a good idea for the water - also water them below the mulch line and not on top, as it will quickly evaporate off the mulch before it soaks in. (it sounds like you are probably doing this). The moisture control potting soil is probably a good idea - you also buy the crystals as an additive. A cheaper alternative is to put newspaper in the base of the pot.

You could try a more shaded area, or erect some shade cloth.

A swings-and-roundabouts suggestion: If you planted them out in the garden (assuming you have one), then the soil will not get as hot. But you then lose the freedom to move them!

I think you're okay for diseases. The damp molds and wilts mentioned in my books imply they're more of a cool problem - not a hot problem.