The Best Way to Water Your Vegetable Garden

Summer can mean hot temperatures, little rain, and water restrictions—all challenges to keeping your garden healthy and productive. To avoid losing any plants on dry days, use these smart watering tips. They include water-reduction techniques, the best way to water the vegetable garden, and how to use sprinklers, drip systems, and ollas.

The garden is baking in sunshine, and where I live, we’re having one of the hottest and driest summers in memory. Fields that are usually lush and green are yellow and withered, and let’s not even talk about the lawn. The ground is thirsty, and if I want the garden to survive the summer heat, I’ll need to start watering and taking serious action.

However, with drought comes public notices urging water conservation and lawn watering. There can even be restrictions on using the hose or sprinkler systems. That raises the question of how we, as vegetable gardeners, can keep our gardens watered while doing our best not to turn on the tap. If you’re looking for ideas, too, these water-saving tips for the vegetable garden will help.

The Best Time to Water the Garden

The time of day you water makes a big difference in how much moisture reaches your vegetable plants. Watering in the day’s heat can mean that you lose much of it to evaporation long before it reaches plant roots. If you water at the wrong time of day, plants can suffer, and you can end up using more water than is necessary. That’s why watering the garden is best done when temperatures are cooler and the sun isn’t fully up.

The best time to water the garden is early morning. Working outdoors will be cooler, and the soil and plants will be able to absorb enough moisture to get them through the hot day. If you can’t water in the morning, then evening is second-best. Watering at these times means moisture stays in the soil longer, giving plants a chance to soak it up and stay healthy.

The reason that morning is better than evening comes down to garden pests, fungus, and disease. If you water in the morning, the sun will dry out the top layers of soil and your plants before evening falls. This means fewer slugs and snails will be out and about destroying young plants. It also reduces the chance of microbes causing infections and disease.

Deep Watering as a Best Practice

The way you water crops in summer matters, and during this time, you should aim to deep water. All this means is that you water until the soil around the plants’ roots is fully saturated. If you casually water the soil surface until it looks wet, you usually only wet the top few millimeters. Try watering this way and then dig around in the soil afterward. The soil immediately below the surface is often bone dry.

To water vegetables well, aim to wet the soil to a depth of about 6-12 inches—this is equivalent to about an inch of water over the entire surface. With fruit bushes, trees, and some perennial vegetables, aim for 18-24 inches deep (1.5-2″ of water). Doing this is called deep watering, and it allows plants to drink deeply and keeps the soil moist for longer.

When deep watering, direct a gentle spray of water onto the soil beneath a plant for as long as needed to saturate it. Avoid watering the leaves, since plants do not absorb water from them—moisture needs to reach the root system. I usually slowly count to 30 when I’m deep-watering containers or individual garden plants, and though it’s much easier to do with a hose, you can use a watering can if you wish.

Using Mulch to Keep the Soil Moist

After watering well and at the right time, we also want to aim to keep moisture locked in the soil. To do this, use mulch. A one- to two-inch layer of organic matter, such as compost, aged manure, or mushroom compost, spread over the soil, will help keep your soil from drying out. By doing this, you won’t have to water your garden as often, and plants will stay hydrated longer.

In hotter regions and drought-prone areas, it’s best to use tougher organic matter as mulch. This could be a layer of straw, wood chips, or grass clippings over the soil. Though low in nutrients, it serves as a more heavy-duty cap that helps the soil retain moisture better than compost. Some gardeners even spread compost, then another layer of tougher mulch on top of it.

In larger operations, such as a commercial market garden or flower farm, the mulch of choice is plastic mulch. It comes in large sheets or rolls, and you can pin it down to the ground and cut holes where you want to plant crops. It can be more practical, but it costs more. There are also questions about whether it leaves microplastics or other harmful compounds in the soil.

Whichever way you go about it, using mulch is the smartest way to keep your garden bountiful. In addition to keeping the soil moist, it protects the soil from erosion, prevents weeds from germinating, and can support soil organisms and nutrients. It’s especially important to use mulch on clay or sandy soil. Clay can turn rock-hard in the sun, and sandy soil can dry out completely.

Drip Irrigation Systems

If you have hot and dry summers, you should strongly consider installing soaker hoses or a drip-line irrigation system. Both work by slowly releasing water at ground level or slightly under the soil surface. It can mean a good amount of legwork to install them, but they use much less water than other systems and can be automated, saving a lot of time later on.

Drip lines and soaker (seep) hoses are attached to a water source, usually an outdoor tap. In the case of soaker hoses, think of them as porous hoses that bead up with drops of water along their length. Drip lines are made of thinner, rigid poly pipes that you snake through your vegetable garden or raised beds. Along its length, at regular intervals, are smaller feeder lines that you can direct to your plants for targeted watering.

Watering the Garden with Sprinklers

Sprinklers can be invaluable watering tools, even though there are arguments against their use due to overspray and evaporation. The benefit is that you can turn them on and leave them, provided you mulch and water in the morning (or evening), a lot of water will be retained.

Figuring out how long you should run it can be tricky, though. I remember the sprinkler being on in my grandma’s garden throughout the summer. It would be around dinner time, and she’d move it around to make sure the garden got a good soaking.

When I use a sprinkler in my garden, I use one that oscillates back and forth or that turns in a 360-degree circle. My current sprinkler rotates and offers several spray patterns to choose from. I always use the ‘flat’ setting to keep the water as gentle as possible.

How Long to Leave the Sprinkler On

I prefer not to use sprinklers in the garden, but sometimes it’s necessary if you don’t have drip irrigation. When I do use one, I turn it on very early in the morning and leave it on for an hour before moving it to another area. This morning, I got up at 5 am to turn it on and left it in one place for an hour before moving it to the next. It seems like a lot, but if you don’t water long enough, watering at all can be pointless.

Different sprinklers can release more or less water than mine, though. An easy way to work out how much your sprinkler sprays is to place a simple rain gauge in the area your sprinkler will hit. Turn the sprinkler on and leave it on for thirty minutes. Measure how much water is in the glass afterward—a vegetable garden in summer needs at least 1-1.5 inches of water every week. Sometimes more!

So, if there’s only three-quarters of an inch in the glass after thirty minutes, add enough time to make up the extra half inch. In this case, that amounts to 60 minutes of uninterrupted sprinkler watering for 1.5″ of water over your garden.

Use Ollas for Deep Watering

Another brilliant tool for keeping your crops watered is the olla. They are unglazed terracotta pots (or cups) that you bury in the soil and fill with water. Terracotta is naturally porous and will wick water from the inside out. If you plug up the bottom of a terracotta plant pot and then fill it with water, you’ll see exactly what I mean. The outside turns dark and damp after just a few minutes. This effect makes them effective underground watering units.

I have made and used DIY ollas for over a decade, and they work! Not only inexpensive, but they also act as a first and last defense against a lack of water. If you keep them filled, you can use them as your main watering source or as a fail-safe if your main irrigation fails. Once filled, the dry soil around the olla will suck the moisture out of the pot. Usually, that leaves the soil around the olla 1-2 inches moist, and plant roots can sense it. If they are able to, roots will grow into that area and even latch directly onto the pot.

I also use Thirsty Earth automatic ollas in two of my long raised beds inside the Polycrub. They are planted down the middle, and each cup is attached to the next with an irrigation line. A large water tank sits at the bottom of each bed, and from it, water gets gravity-fed to each olla cup. It’s absolutely genius! This product is currently available only in the USA, and you can get a 10% discount on olla watering systems with code lovelygreens.

Overhead Irrigation

Outdoor sprinklers are one kind of overhead watering, but you can install other kinds in your undercover spaces. Large commercial greenhouses and polytunnels can be fitted with a network of pipes and dangling sprinklers—they are particularly useful for seed beds, growing high-density greens, or cooling plants down when it’s really hot.

You can also install automated misters under smaller tents made with fleece or plastic sheeting. These are typically used for propagating cuttings or growing houseplants, though. If you are considering overhead watering, be aware that excessive moisture on foliage can lead to disease and rot, especially in enclosed spaces. Using soaker hoses and drip lines to irrigate established plants might be a better option for you.

Shading and Ventilating Plants

There is another very important aspect to keeping crops watered and productive in hot summer sun. It’s providing some kind of shade or shelter for them. Watered well, many mature plants can withstand direct sun, and then spend the night recovering. Young plants, plants in containers and pots, and tender-leaved plants of any kind can suffer more, though. Vegetable gardens in subtropical and drought-prone areas can be at risk of sun scorch and water loss, too.

To give plants protection, lift and move containers into a shadier area, if possible. In the garden, you could grow plants such as lettuce in the shade of another crop, such as under a cucumber pallet trellis. It’s also common for gardeners to erect a shade cloth either over the garden or over the greenhouse to protect the plants underneath. The cloth is usually a dark or green mesh that allows some light through. I also paint my greenhouse with shade paint if I have crops growing inside in summer. It’s a non-toxic whitewash that you can clean off at the end of the summer with soapy water.

Ventilation can also help cool undercover growing spaces. On hot days, throw open the doors, windows, and air vents to increase air flow. Early in the morning, I also spray the floor of my greenhouse with about a gallon of water. This helps cool the inside temperature, but should only be done if there’s plenty of ventilation. Evaporated water increases the humidity, which can cause fungal diseases and rot.

Collect Rainwater

Saving rainwater is incredibly satisfying, and it comes in handy if you do a lot of hand watering. It can be collected in gutters that drain into rain barrels, dipping tanks, ponds, IBCs, or underground cisterns. The most common way is to attach a rain barrel (water butt) to the downspout of your home’s guttering. They can also be adapted to collect water from sheds and greenhouses.

Having a rain barrel can be very helpful for watering plants, and the soft water is ideal for seedlings and houseplants. In a drought, most saved water doesn’t last very long, though, especially if you have a lot of plants to water. I know someone who buried a one-thousand-liter rainwater storage tank in her one-acre garden. She was initially very pleased with it, but found that the water inside lasted less than a week during the first drought. Just something to keep in mind if you have a large growing space.

Recycled Water for Plants

If you are trying to save water (or have to), you can use recycled water from the home to water your plants. This can come in handy if you are facing water restrictions in your region. Dish soap, shampoo, and soap can be harmless to plants when diluted in water—especially if you use eco-friendly products. That means you could save your dirty dishwater and bathwater for use in the garden without fear of harming your plants.

Be a little more cautious, though, if you use conventional products with a lot of fragrance, boron, or additives. They can build up in the soil and on your crops. If you do want to use graywater, try to use products labeled as graywater-safe and/or direct the water away from edible parts of the plant.

From a practical standpoint, you could harvest graywater by using a plastic tub in the sink for washing dishes. Being able to lift it out makes it very easy to take to the garden. In the case of greywater from the sink, tub, or washing machine, you may have to either bail it out or install custom plumbing. Only the most determined or eco-dedicated gardener is likely to do this, but where there’s a will, there’s a way!

Growing a Resilient Vegetable Garden

We’ve just gone through quite a few watering and gardening techniques for hot, dry weather. You might want to try all of them or just a few, but it can make an incredible difference to your own garden and its yield. Keeping on top of watering helps prevent powdery mildew in zucchinis and squash. It also prevents onions from bolting, turnips from going woody, and tomatoes from developing blossom end rot.

If you fail to water your garden, especially if it’s unmulched, plants can die or sicken. The soil will suffer, too. Potted plants will shrivel, and the potting mix might dry out to the point where it no longer absorbs moisture. All of the hard work you put into sowing seeds and planting out will have been in vain. So, be mindful and actually feel the soil to see just how dry or wet it is. With good watering, protection, and mulch, your crops will survive and be productive through almost any heat wave. Here are a few more ideas on growing a resilient garden:

• How to Grow Vegetables During a Drought
• 70+ Perennial Vegetables to Plant Once and Harvest for Years
• How to Make DIY Ollas (simple plant waterers)