Watering Wisely in Drought or Hot Weather

Plants drink their food. If your soil dries out, your plants will starve—or wilt. We often hear that vegetables and flowers need “an inch of water” per week. This doesn’t seem like much but if you spread that inch of water out over a 10x10 foot space it equals 62 gallons! What’s a gardener to do, especially when some areas have restricted or even banned outdoor water use?

12 Tips for Gardening in Dry Weather

Drought in many regions, long dry spells, and atypical weather patterns have many gardeners challenged and rethinking their use of water so it’s not wasted. Let’s go over some of the best ways to water wisely and also conserve moisture.

1. When to water? The best time to water is in the morning between 4 AM and 9AM. Why? This way you avoid evaporation; watering in the afternoon or in weather above 90 degrees may cause up to 50% of your water being lost due to evaporation. In addition, you avoid disease risk which can happen when foliage stays wet at night. If you can’t water in the morning, water in the later afternoon or early evening. 
    
2. Water deeply, less often. Stop sprinkling your plants! The rule of thumb is: Water heavily and infrequently, NOT lightly and infrequently. Water is for the plants’ root system so that it can seek out nutrients and moisture as well as become more resilient; it’s not for the leaves and weeds.
   • For young plants and warm-weather vegetables such as tomatoes and cucumbers, you may need to water every day or two. For shallow-rooted plants such as bedding plants and leafy vegetables, a good soaking once a week may still be fine. Shrubs such as hydrangeas also need a deep, weekly watering.
   • How much water? For plants that are well rooted, the water needs to saturate the soil at least 10” down where the roots grow! Most sprinklers need to run for 60 to 120 minutes to apply the correct amount of water to an area. A slow, saturating soaking at a lower water pressure is much better than a fast, high pressure watering. 
   • Check the soil moisture at root level if you’re unsure in the beginning; dig a small hole with a trowel. If it’s cool and damp, just move on. We also recommend a cheap water meter; they come on a spike that you quickly put into the ground in different areas and will tell you when to water.
   • Container plants will need to be watered every single day when it’s super hot; water gently until it flows from drainage holes in the container.
   • The plants in a crowded bed should be watered significantly more than a more open garden bed or singular shrub.
      
3. Trap water. Plant into natural depressions where water pools. Or build up soil around plants to capture water. Another idea is to build up small berms to create miniature reservoirs that hold the water in place so it has a chance to soak into the soil and avoids runoff.
   
   
   Or, sink a plastic pot into the ground up to the rim next to especially thirsty plants (example: squash). Water into the pot which will then feed the water directly to the root zone.
   
   
4. Watch for the two “indicators” from plants. Droopy plant leaves are an easy cue that it’s time to water. (The first crops to wilt are usually squash or cucumber.) Don’t worry too much; by the end of the day and the temperatures drop, your plants should recover. A second cue of water dehydration is the browning of the leaf edges and also between the veins of the leaf. If the leaves feel crispy versus soft, that’s leaf scorch.
    
5. Water at the plants’ roots, not from above! Never water the plants’ leaves! Aim water at the base of your plants on soil level. Keeping foliage dry has the added benefit of reducing disease problems. 
   
   Photo: Aim water at the base of the plants, not leaf level, to avoid wasting water as lower foliage disease risk.
    
6. Weed! Unwanted plants in your vegetable bed is simply competition for soil moisture, so keep on top of them. Annual weeds can just be hoed off and left on the soil surface, but take the time to dig out the roots of more pernicious perennials such as bindweed or ground elder. Smother weeds or pull them out—roots and all. Don’t make your plants compete with weeds for moisture.
    
7. Protect plants from water loss by using shade clothes in hot weather and protecting plants from wind with windbreaks. Use taller crops such as corn to also cast shade and protect smaller plants. Sprawling vines also protect the soil.
    
8. To automate watering, look into soaker hoses or drip irrigation. Soaker hoses have tiny pores which deliver a slow, steady soak to just the areas you want to water without wetting the leaves.  An inch of water slowly dripped onto the soil over a six hour period will soak in and not run off. Dig into the soil an hour after watering to see how deep the moisture went. Adjust the flow and timing accordingly.
   • If you already have an irrigation system, be sure to check the emitters each year as the may watering plants or shrubs that no longer exist; cap them off or move them to avoid waste. Learn how to plan irrigation for your garden.
   • If you are using a sprinkler, use a rain gauge or tuna can in different parts of your garden and measure the water. This helps you test the spread of water over your lawn and see if the sprinkler is watering evenly, so you can make adjustments. Once you get a sense of the watering schedule, consider using timers. Also look for sprinkler heads that use larger droplets (vs a finer spray), as you will be less likely to lose water due to evaporation.
   • If you are watering with a hose, avoid wasting water by using a long watering wand with a push button or easy shutoff lever. This way you can carefully water each plant at ground level. 
     
     
9. Over-watering plants can be just as damaging to plants as drought. See our chart on when to water vegetables.
    
10. Incorporate lots of organic matter. Rainwater sluices through pure sand at the rate of 20 inches per hour or even faster, taking with it everything plants need to survive. Soil with lots of organic matter slows the transition of water from the soil to the subsoil, giving plants a chance to take in what they need. This is critical for a good garden and even more important during a dry season. Build up your soil by adding lots of compost. Good soil absorbs water like a sponge and improves water-holding capacity.
     
11. Mulch around the base of your plants to cool the roots and conserve water. Place straw, bark, pine needles or leaf mulch around your plants to help slow the evaporation of water from the soil. Or, use whatever you have at hand—newspaper; black plastic; old carpet; large, flat stones—and apply it when the soil is wet. (Don’t mulch with peat moss; it dries out and forms a mat on the top of the soil that easily sheds water.) 
    • It takes 1 inch of water 8 times longer to evaporate from mulched soil than from bare soil.
    • Mulch prevents compaction and acts as a cushion during heavy rainfall helping water to soak in rather than run off. Runoff not only wastes water but can pollute nearby streams. Bare soil can lose up to 3/4 of the rain that falls on it to runoff and evaporation.
    • Mulch moderates soil temperatures and also squelches those weeds that compete with your plants for precious moisture.
       
12. Collect rainwater off your roof, greenhouse, shed, and gutters into water barrels close to where you’ll most need the water. Learn more about rain barrels.

Let Your Lawn Turn Brown

If the lawn is turning brown or yellow, it’s moved into dormancy and temporary stopped growing; this is natural and a way that cool-season grass protects itself to conserve water. We would suggest you let it remain dormant; in the fall when the weather cools or when it starts to rain again, the lawn will emerge from dormancy and start growing again.

If you are going to water your lawn during drought to keep your grass green, you may need 2 to 3 inches of water per week.  Apply in 2 to 3 watering sessions on a very consistent schedule because this level of watering is needed to keep the lawn out of dormancy. Otherwise, let it go! It’s very stressful for a lawn to be forced in and out of dormancy.

Also, do not fertilize your lawn as the lawn is dormant; fertilizer tells the plants they need to grow and they’ll need even more water.  In the fall, when the weather cools down and the grass starts growing again, you’ll do lawn maintenance.

Other tips for conserving moisture: Be sure to keep the grass longer. Why? It dries out faster when short; long blades will shade and cool the lawn. 

In drought, avoid mowing the lawn and stepping on the grass. The grass has stopped growing and mowing only adds stress. If you mow, keep it to a minimum (such as shady spots) and mow high; let clippings fall.

A Word on Trees

Trees should be your very first priority in a drought. Don’t worry about established trees as they know how to survive drought. But don’t be surprised if you see shed older limbs or leaves as protective mechanisms.

However, if you have new trees or even trees less than 5 years old, water them deeply every week to 10 days during drought. When you water a tree, don’t bother watering right at the trunk’s base as this wastes water. The roots of the tree are at the “drip line.” This is the outer edge of limbs. Water the entire canopy of the tree.

Coping With Food Gardens in Drought

1. Strip off leaves: Large, bushy tomato plants lose a lot of water through their leaves. Once the green tomatoes reach their full size, strip off most of the leaves to reduce evaporation and keep water going to the ripening fruit.
2. Harvest at once: As soon as a fruit or vegetable is ripe, remove it from the plant. Pull up any plants that aren’t productive or that are past their prime.
3. Keep plants closer together: Leaves from neighboring plants will shade the soil, helping to conserve surface moisture and reduce weed growth. 
4. Plant less: Take stock of what you really need to grow and don’t exceed your calculations. For example, two or three hills of zucchini and cucumbers will easily meet the needs of a family of four.
5. Check your garden daily! As discussed above: mulch well, weed diligently, and water at the right time of the day.

Watch how we water plants for healthy growth.