Watering during a heat wave

We are due for very hot weather this week here in the greater D.C. metro area. In my little micro-climate, we're to expect highs 98-99, lows 65-75.

I've been watering once or twice a day up until now, except when cloudy or it just doesn't seem to need it. I'm sure those of you down south are used to even higher temps, but I'm wondering... should I add a third watering, even if the soil seems damp from watering earlier in the day? I don't want to over water. :?:

I live in Georgia, and I usually only water once per day (maybe twice if it's really dry and sunny). The Mel's Mix is really good for people who don't know how much to water - Mel says you can't over-water it! So my advice to you is to water whenever you feel like it, and at least once or twice a day while the hot weather lasts, or when the soil looks dry.
I also check the weather.com gardening forecast each day, and it tells me how much to water.
http://www.weather.com/outlook/homeandgarden/garden/weather/tenday/USVA0462?lswe=Manassas%2C+VA&lswa=GardeningForecast&from=locator
for "Very High" I usually water twice, usually don't water for "Low" and I water once for everything else.

Thanks! This looks interesting, too. http://www.weather.com/maps/activity/garden/eastcentralussoilmoisture_large.html

You need to be just a little bit careful about overwatering during extreme heat. Nothing to do with Mel's Mix, more to do with watering heat-stressed plants. My garden experts at my favorite local nursery tell me that the plants can't take up water when severely heat stressed whether they are drought stressed or not. If you water during extreme heat (over 100 or so) then wet roots will just rot.

If your soil feels plenty moist at root level, you should not need to water again that day. If your plants look a little wilty and don't perk back up by the cooler evening, then you should water (that's the rule for flowers). I personally don't like to wait for something in the veggie garden to get drought stressed enough to look wilty, especially since a hot, dry, windy day can just suck the life right out of the plants, let alone what it does to production. If I'm expecting heat and especially wind, I water in the mornings even if the soil is a little moist, still. If it's quite moist, my garden won't need water that day.

Thanks very much.

I'm in that same yellow area as you are Megan! We have not had a significant rain for over three weeks and our new rain barrel has been empty for almost a whole month! We are watering once a day, twice for some plants. I have put straw down around the tomatoes and tomorrow we'll do the peppers. Plants that shade there on squares, we'll leave un-mulched.

We went away for a day and a half for a family picnic and had watered before we left. The soil under the straw mulch was still damp, so I do think it really helps.

The grass in our yard is almost totally brown now and crunches underfoot. But, on the bright side, our SFG looks like a little oasis amongst all that brown. I do hope it rains so though, I have this fear that the city will start limiting water usage if this drought goes on much longer.

Patti

All my plants died over a period of just a few days of extreme heat (30-35C here is extreme...).
They were well watered too (just prior to the heat we've had daily heavy rains for weeks), everything just burnt to death under the scorching sun.

jtwenting wrote:All my plants died over a period of just a few days of extreme heat (30-35C here is extreme...).
They were well watered too (just prior to the heat we've had daily heavy rains for weeks), everything just burnt to death under the scorching sun.

\

Did you water during the heat wave?

We had a heat wave a couple of weeks ago then it dropped into the mid 80's. The heat wave is supposed to return today. Ugh. I'm thinking I may need to drape some sheets over some plants (that's the only thing I have to use for shade). I noticed 1 or 2 pepper babies have dropped off and I'm thinking it's from the heat. I just don't know how much heat the plants can take, especially since the root system is so close to the top in a raised bed. With cardboard and weedcloth underneath unfortunately the roots can't go down to where it's cooler. I think I need to find some hay to mulch with for protection. Water bill is going up because of having to water the garden so much. It's been at least 3 weeks since we've had any significant rain - or any rain at all. With us too, the grass is turning brown and crisp. Burning ban has been started in the city and by permit only in the county. (Fireworks even started some fires.)

I forgot to mention, during the last heat wave, especially because some tomato plants had wilting leaves, I watered a lot hoping that would solve the problem. Ended up with some tomatoes getting blossom end rot. Do be careful not to overwater.

We haven't had significant rain since April, and not even a light shower since mid-May. Our pasture is becoming non-existent, and our hickory tree is dropping its nuts. We had an entire week of temperatures in the high 90's or over 100 with high humidity and heat advisories for the entire time. We only watered every other day, and sometimes every three days, but we gave a good soaking when we watered. Some of our plants are in boxes with Mel's Mix, and others are in ground beds with a mixture of rice hulls, compost and cow manure. It didn't seem to make much difference in the amount of plant stress. They were all stressed, but they all survived.

The tomatoes in Mel's Mix have continued ripening although they did not set much new fruit during that time. The jalapenos and watermelons have continued setting fruit, and we picked a mess of purple hull peas during that time, as well as cut a few pods of okra. The corn, beans, squash, and cucumbers seemed to stress the most. Our beans have never looked good, and the squash, muskmelon, and cucumber blossoms fell off without pollinating. They probably needed more water than we gave them, or it may have been due to the heat.

Once the temps cooled into the 80's it was amazing how much better everything looked in spite of the drought. Now we're back up in the 90's again, but that's par for southeast MO in the summer. I just wish it would rain.

We have also been in a record setting heat wave in Maryland, so I water before I go to work and after I get home. I have also been experimenting with 50% shade cloth draped over my garden enclosure and trellis. So far, so good.

Mikesgardn, That's a wonderful garden! I love your setup with the shade cloth! I've already spent my limit on gardening this year or I'd do the same. I'll make do with what I can find (probably sheets) but next year I want to do that! Let us know how it works for you.

Bec, I would strongly recommend that you mulch with straw instead of hay. Hay contains millions of weed seeds that you really don't want to introduce to a square foot bed -- trust me on this. Wheat or oat straw may have a few grain kernels that will germinate next spring, but you'll easily be able to recognize and pull any such plants.

If you want to keep your plant roots really cool, you can put down a nice layer of newspaper and cover that with straw.

Junequilt - okay - now I'm going to expose my ignorance. I thought straw and hay were the same thing. What's the difference and where do you get straw? I do have pieces of cardboard on top of the soil on some of my tomato plants in pots. I could at least do that for more plants and also the newspaper until I get straw. (I have a small stack of newspapers I haven't used yet. Didn't think about doing that.) Thanks for your input. It's greatly appreciated.

Straw and hay are very different, but easily mistaken for each other because appearance is similar. Hay is a feed comprised of various long dried grasses and other nutritional plants such as Bermuda grass, alfalfa, and clover. Livestock eat it during the winter months when little pasturage is available. Straw is the hollow shaft left over from the harvest of grain crops such as wheat or oats, and although livestock can eat it, it's more often used as bedding. Hay has zillions of weed seeds, straw virtually none. When you buy a bale of something for garden mulch, just make sure you specify straw.

I've tried both hay and straw, since Ruth Stout (http://www.organicgardening.com/feature/0,7518,s-5-21-189,00.html) recommended mulching with hay. It did seem to feed my plants -- whereas straw really just kept them mulched -- but also introduced several types of weeds to my in-ground garden areas that I never had before. It turns out Stout lived near the Connecticut coast and used salt hay, which is a very different thing.

You can spread several layers of newspaper, moisten it, cover with straw, and sprinkle lightly with bloodmeal. The nitrogen in the bloodmeal will help the newspaper and straw gradually decompose without robbing nitrogen from the soil.

Thanks for the information. I actually read Ruth Stout's book years ago and have been looking for it recently - must be in storage. I'm thinking of incorporating her method with Mel's method. I know he liked that method so much he taught it before coming up with the SFG method (because he thought the Ruth Stout's method was too messy.) Thanks again for your input and help.

I mulched only some of my garden with some grass clippings and it really makes a difference in the temperature of the soil. I was pretty surprised. I was actually a little worried that it was too cool for awhile there. Mulching makes a difference - cools soil and retains moisture.

One way to remember which has seeds: hay vs straw - people are called hayseeds, but no one is called a strawseed.

So far, my plants are doing okay. My garden is on the north side of the house, guess that is playing to my advantage for once. My misting system is becoming very popular with the local birds, though.

Chopper wrote:

jtwenting wrote:All my plants died over a period of just a few days of extreme heat (30-35C here is extreme...).
They were well watered too (just prior to the heat we've had daily heavy rains for weeks), everything just burnt to death under the scorching sun.

\

Did you water during the heat wave?

The heat started thursday, was too much glare and heat to water until sunday when it was already too late (always been told not to water during extreme heat or sunny conditions as that will make things worse).
It was not lack of moisture that killed things (as I said, everything was soaked through from constant rain before, the air extremely humid too) but purely the heat.
Wouldn't be surprised if the crop literally cooked to death.

A lot of people say not to water but it doesn't make sense to me. Just like people, spraying down the plants would cool them off. The magnifying glass theory doesn't make sense to me. A little shade may have helped too, but that isn't always easy to do. Temps under 100F in the middle of summer don't seem like enough to destroy a crop. Easy for me to say, it wasn't my crop that was destroyed.

My opinion, which means exactly nothing, is that watering during the heat wave would have been helpful. At least, that is what I would do, and have done, to no ill effect. But, I may have just been lucky.

The temperatures itself were not likely the main problem, but the sudden change in temperatures combined with unrelenting solar radiation on crops not accustomed to them.

Temperature shock, these of course aren't varieties selected for a tropical climate
oh well, time to rip everything out and start from scratch I guess. I've some seeds left, maybe they'll yield a crop come autumn if the summer lasts a while.

Good luck JT.

When we were in the midst of the heat wave we went against conventional wisdom and watered in the evenings. It seemed to cause less stress to the plants, and we didn't have any mold or fungus problems.