How Much & How Often Should You Water Your Tomato Plants?
Struggling to come up with the perfect watering schedule for your tomato plants? Some gardeners will water them too much, and some seem to underwater their garden grown tomatoes. In this article, gardening expert and homesteader Merideth Cohrs walks through exactly how much water your tomato plants need, and how often they should be getting watered.
I have grown tomatoes in my garden for many years now. During that time, I have experienced numerous pest issues, problems with disease, nutrient deficiency, and blossom end rot. Despite all this, even in my earliest years, I was still able to enjoy a small harvest of home grown tomatoes. Why is that?
Plants want to grow. Fruit setting plants like tomatoes will do whatever it takes to produce fruit because this is how they propagate more tomato plants. But we don’t want our tomatoes to just ‘make it through’ the season. We want our plants to be healthy, robust, and produce so many tomatoes that you have to give some away.
One of the key factors in helping your plant stay healthy and produce a lot of fruit is proper watering. Proper watering can stave off disease, prevent blossom end rot, and minimize issues with nutrient deficiencies. So how much should we water our tomato plants? And how often? Let’s discuss the answers to these questions.
There’s no doubt about it, tomatoes are pretty fussy when it comes to getting the right amount of water. Too little water and the plant won’t thrive.
Too much and the roots rot causing the plant to not thrive. In a worst case scenario, you go too far in either of these directions and you ultimately kill your tomato plant. It’s a delicate balance and we are always seeking the goldilocks solution.
Underwatering, while less common, can also cause issues with your tomatoes. You will likely notice yellowing leaves, wilting leaves and stems, and a failure to thrive.
All doom and gloom aside, it’s actually pretty easy to learn how to correctly water your tomatoes. It may take a little bit of practice at first, but soon enough, you’ll have a feel for it and you won’t need to be worried about over- or underwatering your plants.
Before we talk about how often and how much to water, let’s explore how to water correctly. While these tips may seem obvious to some, they represent common mistakes that many gardeners make.
Your tomatoes need a regular and consistent amount of water to thrive and produce as much fruit as possible. You won’t do your plants any favors if you quickly flood the soil every few days and call it done. This is the equivalent of you drinking from an open fire hydrant. You’ll get some water, yes, but you likely won’t be satisfied.
Ideally, you can set up a drip system in your garden. Turn it on in the morning for a few hours and happily go about the rest of your day. If a drip system isn’t possible, or if you’re planting in containers, use a slow flow hose. This will allow you to deeply water your plants without creating unnecessary runoff.
Whether you use a drip system or a hose, be sure to water at the base of the plant. One of the biggest mistakes new gardeners make is to water the leaves (e.g. the top of the plant).
This can cause several problems including pest attraction, leaf burning, and certain fungal diseases. Instead, focus your watering on the soil around the plant so the roots receive the water they need.
Mulching For Moisture Retention
Mulch is incredibly important to your tomatoes. Mulch provides protection against excessive heat, helps the soil retain moisture, prevents water splash back (which can spread fungal disease), and discourages weeds.
You can use a lot of organic materials as mulch. Straw, grass clippings, wood chips, and crushed up leaves are all things you can repurpose from your yard (if it hasn’t been treated with herbicide/pesticide).
You can also use mulch purchased from your local nursery or garden center. Personally, I love to use coconut coir as mulch. You can purchase mulch blocks that just need a soak in water prior to use.
No matter what type of mulch you choose, aim to apply a layer 2-3” thick for maximum benefit.
Wouldn’t it be great if we could water our tomatoes on a set schedule and they would be just perfect? I agree that that would be pretty amazing, but unfortunately nature doesn’t work that way too often.
How much water your tomato plants need is going to depend a lot on your climate, how much rainfall your area receives, the type of soil your tomatoes are planted in, whether they’re in the ground or in containers, and the stage of life they’re in.
If you live in a hot, arid climate, know upfront that you have to water your tomatoes more frequently. On the other hand, if you live in a humid climate that receives a fair amount of rain, you will water less. I highly recommend joining local gardening groups in your area for location-specific recommendations on caring for your tomatoes. What works in one area, may kill your plant in another.
But when it comes to rainfall, my advice is pretty simple. After periods of heavy rain, your plants will not need to be watered for a little while since they have access to water deep in the soil. To ensure your plants don’t receive too much water after a rain, be sure to let the soil dry out adequately or you run the risk of creating a situation that promotes root rot.
Interestingly, one of the most important considerations for properly watering your tomatoes is ensuring the soil composition is correct. Tomatoes require an organically rich, fertile, well draining soil to thrive.
If you are using raised beds or containers, choose a well-draining potting soil and add organic material at the time of planting. If you’re planting directly in the ground, you will likely need to amend your soil ahead of planting to ensure its light, loamy and aerated (this will prevent soil compaction).
Good drainage is very important to tomatoes, and they prefer the soil to begin to dry out between waterings. If you struggle with heavy clay soil like I do, you will need to add amendments to improve drainage. Coconut coir is an excellent choice for this since it improves airflow even when wet, lightens heavy clay, and aids in moisture retention.
If your tomatoes are planted in the ground, they will need less water than those planted in containers or raised beds. The soil naturally dries out quicker when it has the ability to drain away.
Stages of Life
The age of your tomato plant influences how much water it needs as well. In the earliest stages of growth, young seedlings need plenty of water to establish a root system.
As the plant grows and roots branch further and deeper into the soil, it has access to more water than it did before and requires less from the immediate surface.
On the other hand, mature plants with larger root systems will need more water than smaller plants since the water is taken up faster from the soil.
A general rule of thumb is to water your tomatoes about 1.5-2 inches per week for a plant in the ground. But as we just discussed, environmental factors like wind, heat, humidity, rain, and soil type can all play a role in adjusting that number up or down. And of course, the age of your plant and the stage it’s in also makes a big difference in how much water it needs.
Rather than trying to measure the amount of water your plant receives in inches (this is actually pretty hard to do…), I recommend that you get a feel for your soil.
Only water your tomatoes when the top layer of soil – what you can feel with your index finger 1-2 inches down – has dried out. This will help prevent any danger of overwatering that tends to arise when you try to water on a set schedule.
As long as you water slowly and deeply, the amount you water will depend on the look of the soil and the plant rather than set numbers. The bottom line is to only water your tomatoes when they need it!
Learning how much water your tomato plants need will take some trial and error at first. And I promise that you will make plenty of mistakes in your first season or two. I know I did!
But as you progress and grow as a gardener, you will develop an intuition that will help you better understand the needs of your tomatoes and all the other plants in your garden. Happy planting!