Water Is Key to a Healthy Raised-Bed Garden

Water is an essential—but often overlooked—part of the kitchen garden setup.

Here's an excerpt from Chapter 4 of my book, Kitchen Garden Revival:

Although the kitchen garden structures provide the foundation and architecture for your space, there really is nothing more important than the soil and water. These are the elements that will fill your garden with life and ensure you don’t just have a bunch of boxes and trellises, you have sprouts and plants and, of course, delicious fresh harvests.

The truth is, you could skip those boxes and the pathways and the trellises. But, if you cheat on the soil and water, you might as well forget the whole thing.

-Kitchen Garden Revival

Not just water, but consistent water is key to your gardening success. Rain water is best but tends to be unpredictable or, in some places, far too rare a resource. Vegetables and fruiting plants thrive on regular and reliable watering schedules, so unless you get exactly 1 to 2 inches of rainfall a week each and every single week, read on to find out the best way to add water to your raised-bed vegetable garden.

I Learned the Importance of Water with My First Kitchen Garden Clients

When I first started my Houston-based garden consulting company, Rooted Garden, I was talking to a raised garden provider about creating DIY raised bed kits for my clients. He told me:

“You’ll do your clients a huge favor if you can plan a watering solution for them from the very beginning. You rarely think about water at the beginning but, then, somewhere in the middle, the presence or absence of a consistent watering plan is what makes or breaks the garden.”

He ended up being right.

For my first few clients, I delivered a raised garden box, bags of soil, plants, and seeds. The watering, however, was all on them, and it only took a few short months for me to notice their plants were struggling. I knew then I would need an up-front plan for how to deliver H2O to the plants for each and every one of my clients. Every garden design since then has included a plan for irrigation, something as automated as possible, even if the client didn't have a formal irrigation system in place.

If you're still getting your kitchen garden set up, I recommend making a plan for water installation now, even though nothing needs to be watered at this exact moment. If you already have your garden space installed, keep reading for some easy watering techniques you can add to your raised beds.

Ways to Water a Raised-Bed Garden

There are a few different ways you can deliver consistent water to your kitchen garden to supplement when you're not receiving rain. Your watering options include:

• watering by hand with a hose or watering can
• attaching a spigot connection
• burying an Oya
• setting up a formal irrigation system

There are benefits and challenges to each method, so choose the one that works best for you and your lifestyle. Even once you've made your choice, it's important to stay flexible and jump in to alter your system as needed.

Hand Watering a Raised Bed Garden

Watering by hand is one of the best ways to conserve water... because it's a bit of a chore, and you're less likely to do it unless it's necessary. You might have once had visions of yourself smiling and walking plant to plant with watering can in hand. It's a nice image, but heading outside every morning and schlepping a can back and forth to your garden can get old quickly.

Hand watering tends to be less consistent than other forms of delivering water to your plants, which means your plants are liable to get stressed out if you forget to water or delay watering a couple days due to travel or life getting in the way.

That being said, I hand water my own garden. I live in an area where I can typically expect some rain, and I supplement with a watering can or a hose when needed. During drier seasons, I spend a long time watering each of my raised beds.

Tips to Water Your Garden by Hand

• Aim the water at the soil and hold the watering can head or hose as close to the soil level as possible so that the water can be absorbed by the roots. Avoid spraying the leaves of your plants. I like to gently lift the leaves of my big leafy greens out of the way so I can water right at the base of each plant.
• Hand water in the early mornings to give your plants plenty of time to dry out through the day.
• Use a spray attachment if you're watering with a hose and switch to the softest spray. Your goal is to imitate gentle rainfall, not give your plants a good power wash. A gentle spray also prevents soil from washing out of the top of your beds.

Using a Spigot Connection for a Raised Bed Garden

This option works best if you've installed your garden close to a spigot or rain barrel. If you've got a spigot nearby, then connecting a timer and drip hose to that spigot is the closest you can get to automation without actually having a formal irrigation system. It's also a great way to deliver consistent water to your plants (meaning on a watering schedule).

Drip irrigation kits are available at most hardware stores. I recommend also grabbing a Y-connector to attach to the spigot so that you can still use the water line for other things.

Supply List to Create Your Own Automated Watering System

• drip irrigation kit
• Y-connector
• battery-operated timer
• pressure regulator
• PVC or poly tubing (with no holes)
• elbow brackets (1 for each raised bed)

Steps to Set Up a Spigot Connection to Water Raised Beds

• Attach the Y-connector to your spigot.
• Add a battery-operated timer to one side of the Y-connector.
• Attach a pressure regulator to the timer to prevent too much pressure coming into the drip line at once.
• Run PVC or poly tubing without holes to carry the water from the spigot to the garden area.
• Once your line has reached the garden area, pull tubing up into each garden, making sure each tube is securely connected to the source.
• Cover the installed line with soil, then add an elbow bracket and attach drip tubing on top of your soil bed.
• If you want your irrigation lines hidden under your garden beds, you can dig trenches during the garden installation process and bury your water lines. Dig your trenches 4 to 6 inches deep to protect your irrigation tubing.

Observe your watering system and adjust the timer to water for longer or more frequently as needed.

Using Oyas for a Raised Bed Garden

A garden olla (pronounced "oya", like the well-known brand) is a porous terracotta pot that allows moisture inside to seep slowly out to water surrounding plants right at their roots. Because it delivers water exactly where plants need it, a little bit of water goes a long way. This is ancient plant irrigation technology that still works great in a modern garden.

If you're someone who travels frequently or who doesn't have much time to check on the garden during a busy work week, ollas are a great watering method for you. You can go up to 7 to 10 days without refilling your pot. This little vessel really takes the guesswork out of how often to water raised garden beds because you simply refill it when it's near empty.

Plus, you don't have to worry about having too heavy a hand with water because plants only take what they need.

How to Use an Oya

• Dig a small hole and bury your Oya up to its neck in the center of your planting area.
• Plant in circles around the Oya, placing plants that prefer more moisture and those with smaller root systems closer to the olla, and plants that prefer drier soil conditions and those that have larger root systems farther away.
• Fill your olla to the top with water. Close the lid.
• Water your garden by hand for 1 to 2 weeks after installation of the Oya to give the roots of your plants time to grow toward the new water source. Eventually, your edible plants' roots will attach themselves to the outside of the pot and pull water whenever they need more.
• Refill your Oya every 2 to 7 days, as needed.
• Water the surface of your soil anytime you sow seeds or add transplants to your vegetable garden until their roots have established.

Using Formal Irrigation for a Raised Bed Garden

Using a formal irrigation system is a foolproof way to ensure water gets consistently to all parts of your garden. All lines are tied to your home's vacuum breaker to prevent water from going back into the drinking water supply, and a timer turns the water on and off at specific times throughout the week.

In terms of ease once installed, this is the best way to water raised-bed gardens. This convenience, however, does come at a price.

While it's possible to hook up a formal irrigation system yourself, I recommend hiring an irrigationist or landscaper to do this work for you. We work with certified irrigation specialists for all of our Rooted Garden installations because we'd rather be safe than sorry when it comes to digging trenches in clients' yards and connecting to their water systems.

Many formal irrigation systems use drip irrigation lines that, again, put the water right at soil level. You also have the option of doing a low spray head.

Tips for Using a Formal Irrigation System

• If you're still setting up your kitchen garden, make sure you choose a location where the lines can be brought to each of your beds with as little digging as possible.
• Purchase a rain sensor that connects with your timer to turn off your system when there’s been plenty of rain.

When to Water a Raised Bed Garden

Picture this: The sun is high overhead, and you’re gazing out your kitchen window to admire your garden when you discover the leaves of your cucumber plant wilting in the heat. While it might be tempting to rush outside and pull out the hose, watering your plants in the middle of the day could cause more harm than good. 

Each water droplet left behind on your plants acts like a miniature magnifying glass, meaning the sun could scorch your wet leaves. That’s why the middle of the day is actually the worst time to water your plants. 

The best thing to do would be to wait and then water your garden thoroughly the next morning. Your plants are resilient and will make a comeback once their thirst has been quenched. 

The Best Time of Day to Water Your Plants Is Early in the Morning

The best time to water your garden is almost always the early morning when your plants are nice and rested. Overnight, they restore their energy and grab nutrients from the soil, and the morning is when they prepare for their day of growing ahead. By getting water to them at dawn, you can help them take full advantage of sunlight. 

I wake up early and use a watering can or hose to soak the soil of my raised beds. If you have drip irrigation or low-spray sprinkler heads installed, you might set your timer to water before you even wake up, around 4 or 5 a.m. 

While you can water at dusk, once the sun is no longer as strong, you don’t want your garden to be wet at night, when most pests show up to attack your plants. 

If you have a plant that’s showing stress, you can always come out in the evening and just water around that plant, not the entire garden. 

How Much to Water a Raised Bed Garden

The general rule of thumb is that most gardens need an inch of water per week. If you haven't received an inch of rain, then that means it'll be up to you, the gardener, to deliver more water. Even if you have had an inch of rain, you'll still need to check your soil daily to determine whether your garden needs additional water.

I wish I could give you an easy answer to how much water a garden needs, but ultimately, both how much and how often you should water raised garden beds depends on a number of factors unique to your setting and can even vary from day to day. 

Watering Needs Depend on Evaporation Rate

One factor is how quickly water evaporates in your atmosphere. The evaporation rate varies from climate to climate. My garden in muggy Houston stayed moist way longer between waterings than my garden in Chicago, where the air was often dry. In drier climates, you may find that your topsoil is already dried out by noon, even if you just watered that morning or had some rain.

It might feel nice and cool outside, but evaporation rates are not just determined by temperature. Wind and humidity also affect rates. So just remember if your evaporation rate is high, you're going to have to water more often.

Note: I would say that understanding your rate of evaporation is an advanced gardener skill. That's why it's important for newer gardeners to just check on their gardens often and stay flexible when something doesn't seem to be working.

Watering Needs Depend on What Type of Plants You're Growing and Where They Are in Their Growing Process

Some plants are just thirstier than others. Constant moisture is vital to your leafy greens like lettuce, spinach, and kale. Lettuce seedlings especially have shallow root systems that don’t hold moisture very well, so they need to be watered frequently to grow. If you let your garden dry out, your seeds may not germinate or your seedlings may not thrive. More established plants are usually a bit more tolerant of gaps in their water supply than younger plants.

Watering Needs Depend on What Growing Season You're In

It may sound counterintuitive, but when my garden is packed in the warm season, I actually don’t need to water as much. My plants shade the surface of the bed, so even though it’s warmer, the garden locks in moisture for longer and prevents evaporation. If it were extremely hot outside and my plants were struggling and no longer shading the soil, I would have to increase my watering exponentially. In the cool season, many of the plants you're likely to grow, like leafy greens, prefer to stay consistently moist.

How Long to Water a Raised-Bed Garden with Drip Irrigation

Remember, the key to watering is consistency, so you'll need to figure out how many times you'll run your drip irrigation based on your evaporation rate, plants, and growing season.

Drip irrigation emits much less water than sprinkler heads and hoses, so you'll likely need to run your system for a number of hours (not minutes) each week to water deeply. Depending on the flow rate of your drip system, the time it takes to deliver 1 inch of water to the soil could be at least 5 hours. That means you'll run your system for 15 to 45 minutes each time several times per week.

How to Maintain Your Water System in a Raised Bed Garden

I can't tell you how many times this has happened: A client calls our Rooted Garden team to say things aren't looking too good in their gardens. We head out to see what's going on and find scorched plants and parched soil. Since we set all of our clients up with irrigation systems, we head straight to the panel...

Only to find that it's turned completely off. Or it's still set to a schedule that worked in January but not now that it's 100 degrees outside in July.

Check the Timer/Panel on Your Watering System

Periodically check the timer on your system to ensure the battery is working, and if you have a formal irrigation system, be sure it's actually turned on. Let your system run while you're outside in the garden space and watch it go through a full cycle to check for leaks, see if any areas of your garden are getting too much or too little water, and overall ensure things are working as they should.

Change Your Watering Schedule with the Seasons

Your watering schedule will likely need to change throughout the year to meet the garden's needs. Wind, humidity, and temperature all play a role in how fast your garden’s water evaporates, so paying attention to the temperature can help you figure out how quickly the moisture in the soil will evaporate. Increase your water at the height of sun and temperature levels and decrease it when temperatures fall in the cooler parts of the growing season. During extreme heat, you might need to water as often as twice a day.

Monitor the Rain

Use a rain gauge to determine how much rainwater has fallen each week. Based on what the gauge reveals, you might decide to turn off your automatic irrigation system or crank it up. Rainy days give hand-waterers a nice little break.

Check on Your Plants

Keep an eye out for signs that your plants are becoming dehydrated, and be ready to make adjustments to your system and update your watering routine or timer.

But, here’s something to remember: The answer to every garden problem isn’t always more water. Many newer gardeners see a problem and run for the hose. Before you add more water, be certain it’s necessary. Here are some signs of water trouble in your garden:

• The garden’s surface is dry and cracked.
• Leaves are wilting and/or turning brown.
• Leaves are turning yellow, mildewing, or rotting.

While these are all signs that your water needs adjusting, the first two indicate your garden is not getting enough water, while the third indicates it's getting too much.

Mistakes to Avoid When Watering a Raised Bed Garden

Keep this watering no-no's in mind to deliver water to your raised beds in the best manner.

• Watering by hand in the middle of sunny day. You'll risk scalding the leaves of your plants and lose more water to evaporation.
• Spraying the leaves of your plants. Most of the water that plants need is taken up by their roots, so aim your water stream where it's needed.
• Watering every day without assessing your garden's actual needs. Make sure to check the moisture level in the soil before giving your plants more water.
• Wasting rainwater. It doesn't matter which watering method you're using—collect as much rain as possible. Nature's water is more than just water; it also contains dissolved minerals that feed your plants in addition to giving them moisture. Unlike tap water, rainwater hasn't been treated with chlorine or additives that can harm your vegetable plants. Use a rain barrel or simply cut off a gutter and have it deliver rainwater to a large bucket. You can then fill watering cans with the best water available for your plants and limit your home's water usage.
• Watering inconsistently. Plants are like people: they thrive on routine. Plants will actually grow better when you water them on a schedule.

So, my friends, those are the basics of giving your plants the vital resource they need to flourish and provide you with lots of delicious returns. Check out the many resources we offer at Gardenary to help you find success growing in raised beds! 

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