When should a garden be watered?

June 22, 2008 8:02 AM

What time of day should the garden be watered?

I live in the Southeast, grew up in the Northeast and have had or been around gardens most of my life. I've always been taught to water the garden at dusk or overnight, the reasoning being that it allows the plants to fully digest as much of the water as possible.

However, since moving to the Southeast I've seen experienced gardeners water their plot during the day or shortly after dawn. Their reasoning is that it's hottest during the day, so you water the plants when they need it most. They don't really give much thought to the idea that the water will evaporate more quickly during the day and tend to regard my idea of watering as foolishness.

Is there an optimal time to do general watering of a garden? Does it depend on the region?

posted by Brandon Blatcher to home & garden (16 comments total)

You're right. At night or in the morning is best.

When to Water Your Garden
posted by Ugh at 8:14 AM on June 22, 2008

I noticed my lawn was much healthier when I began watering at night.
posted by HotPatatta at 8:21 AM on June 22, 2008

Heh. Depending on where you are, watering times may be set by the local government as required by local conditions.
posted by jquinby at 8:23 AM on June 22, 2008

In the Southeast early morning or evening is best. I think you can't go wrong with early morning waterings anywhere.

In humid areas such as Florida, where I live, I've always been taught to water early morning because plants that are susceptible to fungus could be affected if watered in the evening.
posted by LoriFLA at 8:23 AM on June 22, 2008

Early morning is generally best. When I water my lawn, I have the sprinklers set to come on between at 4 a.m. The wind is usually still and the grass dries off after the sun comes up. Watering in the evening can be bad because the extra moisture stays on the plants all night and can cause fungus and mildew.

If you don't have fungus or mildew problems, there is nothing wrong with watering at night.
posted by Ostara at 9:10 AM on June 22, 2008

My grandmother always said "Don't let them go to bed with their feet wet." Smack in the middle of the country. She and my grandfather were farmers, FWIW.
posted by middleclasstool at 9:18 AM on June 22, 2008

The people around you have confused plants and people. Morning or dusk is better than night or day, but morning is somewhat better than dusk.
posted by oddman at 9:23 AM on June 22, 2008

Dusk is fine in a dry climate like the southwest, but in a moist climate wet plants at night can lead to fungus problems. This leaves dawn the best time to water to and conserve water. Later in the day, especially if you are sprinkling, much of the water will evaporate before it even gets to the roots.
posted by caddis at 9:38 AM on June 22, 2008

Snails and slugs love when you water at night.
posted by pracowity at 9:53 AM on June 22, 2008

Depending on how hot it gets, the answer may be "both". I've got about a week before I have to water the containers and tomatoes twice a day because of the heat and wind.

When I water in the evenings, I try to get it done just as soon as the sun's off them in the evening/late afternoon, which gives them a couple of hours to soak in before dark.
posted by Lyn Never at 11:45 AM on June 22, 2008

Depends on whether you're primarily interested in conserving water, or encouraging growth. Watering at night will reduce evaporation, and reduce watering needs, watering at other times might be better for plant growth.

If your lawn consists of native/local grasses you should probably water at the same time of day as when you get the most rain, as the plants will be adapted to that.
posted by blue_beetle at 12:22 PM on June 22, 2008

Early morning, because not only do slugs love those evening waterings, water on the foliage that doesn't evaporate makes fungal leaf diseases spread more easily.

In the case of say, a Sunday where you stayed out late and therefore didn't get up for anything qualifying as morning per se, late afternoon is okay, use the soaker setting on your sprayer if you have one and and keep it down at the base of the plants. (Off to water the garden now.)
posted by desuetude at 12:29 PM on June 22, 2008

My mother, a landscape architect, always tells clients to water just before sunrise.
posted by NotMyselfRightNow at 12:35 PM on June 22, 2008

i'm in hawaii in a hot, dry area/season working on a farm, and i had been militantly against watering during mid-day due to evaporation, wasting water, etc. But my boss farmer pointed out that the hottest times of the day are actually when plants need available moisture the most, so if possible, its good to design a system/schedule to allow to do this. For us this means using drip tape so the water source is in direct contact with the soil, reducing airborne evaporation from sprinklers or spray hoses. As far as evaporation from the soil surface once it is saturated, you can use a good mulch.

All that said, you could also just give your plants a good watering in the morning and have a good mulch cover, to get them through the hot times of day.

I personally don't water at night due to fungus/pest issues. I might water in afternoon but I always leave at least an hour or two of daylight for the leaf surfaces to dry before dark.
posted by dahliachewswell at 1:06 PM on June 22, 2008

The method by which the water is delivered to the garden is perhaps equally important as the timing of the delivery. Using drip irrigation where the water is applied directly to the soil rather than sprinkling it down over the tops of the plants can help relieve a lot of plant disease and insect problems as well as provide a much more efficient use of water. I use drip irrigation on my raised-bed square-foot garden in Iowa and it's great. It's also a whole heckuva lot easier than lugging garden hoses around from spot to spot and getting soaked trying to find just the right position for the sprinklers. A great resource is DripWorks. Order their catalog - it's great garden p#rn!

Try some drip irrigation and you'll find that the timing question becomes secondary - plus you can put your drip system on a timer/meter and let it do its thing unattended.
posted by webhund at 2:13 PM on June 22, 2008

Soil temperatures are pretty constant; if you've got a good layer of mulch and water can easily move through your soil, watering at night is not going to save much water, if any. Perhaps your mulch will have more of an opportunity to absorb water before it evaporates, but if you have decent soil and mulch there won't be much effect either way. As far as drip goes, it has advantages, definitely; but in the twelve years I've spent caring for gardens and working with drip (including doing untold number of installations), I have to say I prefer overhead watering. We have problems with mildew, scale, and thrips here, and overhead watering helps those conditions- however, it entirely depends on what diseases and insects are most prevalent in your area, and how healthy your natural ecosystem is. Deep, infrequent overhead watering just before the sun rises works very well in my Bay Area gardens.
posted by oneirodynia at 12:12 PM on June 23, 2008