The Biggest, Best Green-Thumbed Gardening Secrets to Giving Your Plants the Right Amount of Water

You may be wondering:

Do I really even need to water? Aren’t there gardeners who rarely, if ever, water?

We’ve discussed how garden plants need about an inch of water per week. However, not many places in the U.S. and Canada receive the 52 inches of precipitation per year required to equal an inch per week. Plus, in most regions, precipitation comes disproportionately throughout the year, often being heavier at times when there are few, if any, plants in the garden. Nevertheless, many gardeners and farmers who live in such areas never water, not once, and have amazing vegetables, fruits, and grains. In fact, many of the most productive areas, such as the corn belt of the Midwest, receive only 25 to 40 inches of rain per year yet produce massive yields without irrigation. What’s the story?

Well, an inch per week is ideal, but the honest answer is that many gardens do just fine with a little less on average. But, there are also a few tricks of the trade for sure. 

The Tricks of the Trade

Surprisingly, the biggest secrets to making sure your plants have enough water don’t involve the act of watering. Some aren’t even really about water at all but instead about other elements of gardening that have a profound effect on its presence in the soil. They all share a common thread, however, of making the best use of and conserving the water you already receive naturally.

1. A Conservation Perspective
2. Mulch
3. Loosening the Soil
4. Planting Cover Crops

A Conservation Perspective

If there’s one theme to Green Thumb Gardening Secrets, it’s how gardeners can set themselves up to take advantage of natural processes and systems that already exist. When we work with these processes, facilitate them in our gardens, and move away from practices that destroy them, we find that these processes and systems do the real work for us in our gardens (of growing soil, growing plants, patrolling for pests, keeping the soil moist, etc.). After our initial investments of time to provide the materials they need (organic matter for soil building, our sunniest spot for our plants, native flowers’ nectar and some pests to eat for our beneficial insects and arachnids, mulch for our soil and plants, etc.), we sit back and let them do most of the actual work.

Watering is one of these processes. As such, the most powerful tool is the perspective to set yourself up to use what’s provided for you to your plants’ fullest advantage. Rain literally falls from the sky exactly where you need it almost once a week (in most parts of the country—sorry, desert dwellers). It may not equal exactly an inch per week, but it’ll be enough for most gardens in most years. And the three other secrets described below will greatly expand your ability to take ideal advantage of this boon.

For those in regions with too little or too much rainfall for an ideal garden, keep in mind that its presence is still a huge help even in both of these cases. Use it to its full advantage. That could mean collecting what little rain you get in rain barrels and other larger catchment systems and/or digging sunken beds that are sloped to one end or corner to keep your plants’ roots as close as possible to the water table and to direct as more of the rain you receive to them. It could also mean sheltering your plants from an overabundance of rain with row covers or hoop houses and/or building raised or double-dug beds to improve drainage and keep your plants higher and drier. In either case, the perspective to take advantage of existing rainfall will go a long way, as will remembering what a gift it is to have water fall from the sky in the first place.

Before moving on, let’s first be clear: Making sure your plants have the right amount of water doesn’t necessarily mean watering them regularly. It simply means making sure the soil moisture is in the correct range. The tolerable range is actually quite large, and, for most regions, the soil will stay in it naturally. The ideal range is smaller and varies for different crops, but two simple steps—mulching and loosening your soil—give you the ability to keep your soil’s moisture almost perfect for every crop in all but the driest and wettest of years and greatly expand your ability to maintain the tolerable range even in these aberrant years.

Mulching

Your biggest ally for making sure your plants have the right amount of water is mulch.

Think of mulch as a moisture (and heat) regulator for your soil. Use it to regulate your soil’s moisture and temperature like you use the thickness or absence of your coat to regulate your temperature. No mulch at all and your soil will get hot and dry out, but even the lightest layer of mulch helps retain soil moisture to an amazing degree. And heavy mulches will keep your soil almost wet (and cool) in all but the driest conditions.

Loosening Your Soil

Part of the reason loosening your soil is so beneficial is that soil needs millions of pores—or air pockets—for the movement of both air and water to be truly healthy. Well-loosened soil has millions of these small pockets of space between the soil particles that facilitate water, nutrient, and air movement.

Not only does bulk water drain better through this loosened soil, but it also, interestingly, helps keep water in the form of general soil moisture close to the surface. This seemingly contradictory fact is possible because loosened soil helps facilitate capillary action. As discussed in a previous post, think of capillary action as what happens if you immerse just part of a porous material in a liquid (e.g. think cloth or cardboard in water or a candle or lantern wick in wax or kerosene): The liquid rises up the material well beyond the height of the liquid itself. It’s not drenched all the way up, but it’s moist.

And the more porous the material, the better it is at pulling moisture upward. Your soil works the same way: Loose (porous) soils are better at keeping water present near the surface because the connected space of the pores enhances the upward pull of moisture toward the surface through capillary action, one of the main drivers in keeping the soil moist near the surface.

The multitude of small pores also provide more room to store water. This extra drainage, capillary, and storage capacity makes loosening soil extremely beneficial for all gardens, and especially so for particularly wet climates.

You can find much more on loosening soil in the sections on soil.

Planting Cover Crops

Although not typically a gardener’s first step in conserving the water in their garden’s soil, cover crops are a powerhouse of water conservation. Like mulch, they provide a blanket over the soil to protect it from intense, evaporating rays of direct sunlight and incredibly compacting and erosive direct impacts of raindrops. Cover crops, however, also provide so much more in terms of water conservation: naturally loosening the soil to provide vastly increased space for water storage, creating more macro- and micro-pores and pathways in the soil to profoundly increasing the amount of water infiltration, and growing the mycorrhizal fungi that produce the glomalin that acts as a “glue,” sticking the soil together in the aggregates that maintain all of this wonderful, water-storing, water-conserving soil structure and great soil tilth.

All of these wonderful aspects of cover crops are explained in more detail here.