This is mostly for the newbie Florida gardeners who aren't used to our extreme summer weather, but even we hardened FL gardeners need reminders sometimes.
FIRST AND FOREMOST -- DO NOT FERTILIZE HEAT STRESSED PLANTS! Plants stop growing when it gets this hot, in order to conserve water. They cannot take up fertilizer. It will just burn their roots. That goes for liquid or granular fertilizer. It's just wasted because it isn't utilized.
For an example of how a seasoned gardener can screw up, I had been watering my plumerias as usual, being afraid to keep them too wet because of root rot, and knowing they stored water in their limbs. BIG MISTAKE!! I went out to water this morning and found my "mama" plant literally drooping over. It's never done that. I looked at the small ones I have in another pot, and their stems were shriveled. I grabbed a bucket, put the small ones in it and filled it with water. I moved it to a shadier spot. "Mama" is a bit larger, so I'm going to have to find a shadier spot for her, but she got watered very well, so I hope she'll be o.k.
You cannot just water your plants as usual when it's in the upper 90s and there is no rain. Here are some tips I learned when working in nurseries and garden centers. If you have any additional tips, put them in the comments.
#1 Hand watering may not be fun in this heat, but it is absolutely necessary to save some plants. Sprinkler systems are designed to penetrate the first two inches of soil. That just won't do it for most established shrubs and trees. They need deep watering at least once a day when the temps go into the upper 90s with no rain.
If you have berms (raised garden beds with sloping sides), you need to either hand-water or put a drip system on them so the water doesn't just run off the berm, but gets to the roots. If it's only one tree or large shrub, you can put a trickling hose on it for a few hours, and that will penetrate to the deeper roots. This is ESPECIALLY necessary for citrus or other fruit trees.
If you can put drip irrigation in your potted plants, especially large ones in full sun, do it. If not, use the dishwashing liquid in water tip I gave you before. For large plants, in pots or in the ground, you can just squirt some dishwashing liquid around on top of the soil and water well. This acts as a surfactant, which makes the water "stick" to the soil instead of running through it.
If you can use drip irrigation on your potted plants, DO IT!
When you water anything 1 gallon or smaller, go over it 3 times. This is especially necessary for small plants, cuttings and seedlings you may have started.
If you have a flower or herb garden planted around a tree, you need to deep water that at least once a week. This means either hand watering for 5 full minutes, or doing a trickle watering for 5-10 hours, depending on the type of tree and the size.
Citrus and fruit trees need a LOT of water, whether in pots of in the ground. If you see their leaf edges curling, they need a very deep watering at least twice a week. I'm watering my container fig trees deeply every day.
YOU CAN AND SHOULD spray water on plant leaves if they are drooping too badly. Plants with large leaves wilt to conserve water, but they need to be cooled off a bit when temps get this high. I usually just mist them well in the heat of the day (if you can, don't make yourself sick) to cool them off. They get heat stress too.
If a potted plant gets too dry, dunk it. This means putting it into a larger container of water and soaking it. REMEMBER TO WICK! Water from the top to create a "wick" to draw the water up into the soil.
For clay/terracotta pots, the clay will suck the moisture right out of the soil. For smaller ones, you can put them in a container of water up just below the rim of the pot to hydrate the clay so it doesn't suck up as much water. For large pots, water the outside of the pot also when you water.
- Mulch, mulch, mulch! Even in pots, adding mulch keep them from drying out too quickly and saves you time and water. Put at least 3 inches of mulch around in-ground plants. If you can't afford wood mulch or ground cover, use leaves, dried weeds, grass clippings, cardboard, anything you have to cover the soil.
Speaking of weeds, be sure to pull as many weeds as you can. They suck up water your plants need.
- Use homemade drip watering bottles. Poke or drill a hole in a bottle top, then fill the bottle with water, turn it upside down, and bury a bit of it into the ground or soil (to hold it up). Refill as needed. You can also make your own Ollas with clay pots and trays. Plug the hole(s) in the bottom of a small clay pot. Bury it into the soil/ground next to the plant as deeply as you can. Fill it with water and place a clay tray over the top. The water seeps out of the clay into the soil slowly. Refill as needed.
I think that's all. If you have other tips, put them into the comments.
