Watering your garden properly can be tricky and confusing. How much? How often? How to water? These are all questions that, at some time or another plague vegetable gardeners.
I don’t believe that there is one all-encompassing answer to these questions. There is no one size fits all solution. What I can do is provide some overall advice on what I believe to be the best practices for watering in your vegetable garden.
The first and most important point
Watering your garden is about getting water to where the plants need it. How the water gets to where the plants can use it is immaterial. If the water is in the soil and the plant can’t reach the water is wasted. The first lesson to learn is that you must put water where the plant can get it and you must keep moisture available.
So the challenge is to find the best way to put water into the soil in a way that allows it to infiltrate into the root zone. A big part of the answer to this question is, “How healthy is your soil?”
Healthy soil allows water to infiltrate efficiently. Sandy soil allows the water to infiltrate but then it continues down too far for the plants to have access. Poor soil that lacks aggregates compacts on the surface and the majority of the water that is applied runs off or pools up and evaporates.
Even with the best technology for water application, if your soil will not allow the water to infiltrate properly, the water will not get into the root zone.
How to apply?
Watering your garden comes down to three methods – sprinkling, flooding, or drip irrigation. Each has its place and each can be very effective if used properly.
Sprinkling is the traditional method of watering landscapes. Whether you use a hose and sprinkler or an irrigation system sprinkling is probably the best method to water large landscape areas, especially turf. In the garden and on landscape plantings, it can have its problems.
Turf is an ideal candidate for sprinkling because it is open and usually relatively flat. Turf lies low to the ground and doesn’t interfere with the water delivery. Sprinklers can deliver an even consistent application to the soil, which makes watering large areas easy. The problem is watering plants that are taller and with broader or thicker leaf covers. Watering into dense landscape plantings can lead to areas being shielded from the application by the leaves of other plants. Dense plantings can lead to an uneven application or even some plants being completely unwatered. This is particularly true in vegetable gardens where plants with large leaves such as melons or squash can prevent the water from reaching the soil close to the plants base, leaving the root zone starved for water.
Our opinion? Sprinkling in a vegetable garden is not an efficient way to water.
Flooding or Drenching.
Row gardeners are familiar with flood or drench irrigation. I can remember my great-grandmother tending her small garden, neatly planted in rows. She would lay the water hose in one end of the row and let the water run down the row between the plants. She grew nice gardens, but she constantly had to hoe weeds in the rows, and the soil seemed to always have a hard crust on top that she was continually tilling to get the water to soak into the soil. I know now that her soil was unhealthy and lacked the organisms and biome to build the aggregates that would have prevented a lot of the problems with water infiltration.
Flooding tends to compound these problems. It requires bare ground in the trenches for the water to flow. Bare ground exposes the soil to the sun and other environmental elements, including weed seeds. Drench watering can be accomplished around plants that are mulched by allowing the water to run down through the mulch to the soil. The problem is judging when enough water has been applied.
If drenching is your option, pay careful attention to the rate of application. Never turn on the water flow full force. More than likely your soil infiltration rate is much less than the flow rate of your water hose which means that most of the water you apply is going somewhere else and not into the soil and down into the root zone. That equals wasted water.
If you must
Let the water trickle from the hose. If you can see the soil, there should be very little pooling and no run-off leaving the area. This method will allow the water to get deep into the root zone of the plant where it can be used.
The downside to this is that it is a slow process if you have a large landscape or garden. You are effectively watering one plant at a time. Watering each plant could take hours of constant attention.
The better solution.
If we want to apply water evenly, at a controlled rate and put it just where the plants can use it most efficiently, we have to consider drip irrigation, especially in the vegetable garden. Drip is also very effective in managing landscape plants for several other reasons.
Drip irrigation systems are designed to deliver a consistent flow rate along the entire length of the irrigation line. The irrigation lines come with built-in emitters that deliver a steady one or two gallons per hour of water. The emitters are generally spaced one foot apart though other spacings are available.
Drip irrigation allows you to put water along a row of plants and deliver a fixed amount of water close to the ground (little or no evaporation) at a rate that most soil can easily infiltrate (no run-off) and in a measured amount making it easy to judge how much water is delivered.
We do this in our raised beds, and we did the installation ourselves. The installation requires no special skills or tools. Most of the big box home improvement stores or garden centers sell the individual parts. There are even kits that come complete with all the parts ready for you to assemble.
Our Drip Installation
Our grow beds are four feet in width. Four feet is a good size since we have access from both sides. In each of our grow beds, we have drip line laid the entire length of the grow bed. We run three lines on the surface of the soil in each bed. The lines are equally spaced in the bed and are connected at each end of the bed to form a giant loop. The connection for the water hose is at the end of the bed, and we use a quick disconnect coupling system.
The drip system assembles easily. The fittings are all barbed push-in style which doesn’t require hose clamps or special tools to assemble. Cut your drip line to the proper length, moisten the end of the barbed fitting and push them together. I will tell you that the hotter the day, the easier it is to insert the fittings. If the temperature is cool or even cold, you may want to use a heat gun to warm the plastic tubing to make inserting the barbed fittings a bit easier.
For a raised garden bed such as ours, the installation requires enough drip irrigation line to make the pattern, 4 90 degree elbows, two tees, a tee adapter, and a female hose adapter.
What it looks like
Here are a few photos showing the actual drip system in one of our growbeds with the quick disconnect couplings. These are available at your big box store, garden center or online and are inexpensive and make moving hose lines and attaching nozzles or other accessories easy.
Figure 1 Various 1/2 inch drip system barbed component and a quick disconnect fitting
Figure 2 Hose connected to the manual timer and one of the quick connects on a drip system in our garden beds.
Figure 3 The drip system in one of our narrower garden beds with the mulch pulled back. This bed is only three feet wide and has two lateral lines instead of three like our other beds.
One other thing you should install is a backflow preventer on your hose connection at the house. Backflow preventers will prevent water from being pulled back into the water system in your home. This is a safety issue and is required by most city water utility systems. These devices are inexpensive and readily available. Contact your local water utility provider for more advice on backflow preventers for outside water sources.
Figure 4 Installing a backflow preventer on your outdoor hose bibs.
One other addition we have added to our system is a low-cost manual water timer. The timer is a spring-driven timer that required no batteries and no programming. Put it on the end of your hose, attach it to the drip line and twist the top knob to the desired amount of time and turn on the water. The timer will shut off the water, and you can return when you remember. If you are like us, sometimes you forget, but our new gardening assistant, Alexa from Amazon (the Echo Dot) will set a handy timer reminder that will alert you when your time is up. The hose end timer is nice because it allows you to start the watering and leave without fear of overwatering and wasting water.
Above ground or underground
We put our drip lines directly on top of our garden soil and then mulch over them. We have found that during the hottest parts of the summer months in West Texas, we can water once a week for 90 minutes and our plants seem to do well. Using a soil probe, I test my garden beds to judge how deep the soil moisture exists. A soil probe is a thin rode that can be pushed down into the soil to test its resistance. Healthy soil offers little resistance to the probe. I plunge the soil probe into the ground until I feel the resistance suddenly increase. That tells me how deep the water infiltration is and where the depth of my healthy soil ends. I like my raised garden beds to have a probe depth of at least twelve inches.
A winter project
Adding drip lines to your garden beds is a great winter project. You can do it in stages, or find a local irrigation parts supplier and buy the entire kit at once. Most of these suppliers are happy to help you if you ask and will give you recommendations on parts, supplies, and installation tips — one word of warning for those of you in Texas. As a homeowner, you are entitled to install your won drip irrigation system yourself. You don’t necessarily need a licensed irrigation installer to add drip irrigation to your raised beds. However, if you are planning on plumbing your drip lines into your domestic water system and adding an automatic controller (which I don’t recommend at all) you will need the advice and services of a licensed plumber to install the connection to your domestic water supply.
Adding a drip system to your vegetable garden beds can make the onerous task of watering your garden almost enjoyable and make your garden watering more efficient in the long run.
For more information on organic gardening, irrigation, soil health, and other gardening and organic lifestyles articles, visit our website at https://westtexasorganicgardening.com