How to Deep Water Tomato Plants

Growing tomatoes is a much-debated topic among gardeners. A key point of contention is watering. Tomato plants need lots of water. However, tomato plants are also quite susceptible to both over-watering and under-watering. 

Deep watering systems, if carefully thought out, can help ensure that each tomato plant receives just the amount of water per week it needs to make delicious fruit at harvest time.


So what are the tomato watering techniques, and how can you deep water your tomato plants? Read on to learn more about this important tomato plant care tip.

Developing A Deep Watering System For Tomatoes

Many gardeners and gardening websites recommend drip irrigation systems or soaker hoses to ensure tomato plants receive an ample water supply. While drip irrigation can offer some advantages for some kinds of plants, tomatoes may not fully benefit from the method.

Proper watering is very important to the tomato gardener. Installing a drip irrigation system can be expensive. In addition, garden tomato plants have deep root systems and require massive amounts of water at different points in their growth stages. 

You may wind up leaving the drip hose on all day, every day, to guarantee the tomatoes receive enough water through the steady trickle delivered by a drip irrigation system.

An alternative to a drip irrigation system is a deep watering pipe. Deep watering pipes are simply drainage pipes or PVC pipes with holes drilled into them. 

These pipes are installed next to the tomato plants, and water is poured into the top. Water then drains out into the soil and reaches all parts of the tomato’s root system.

The advantage of the pipe watering method is that each plant receives exactly the amount you choose to deliver when you deem it necessary. There is less danger of over-watering or under-watering your plants, and you can adjust the watering for each plant according to your observations.

While drainage pipe or PVC pipe is not cheap, the pipes can be removed easily at the end of every growing season, stored, and reused the next year. Properly cared for, the pipes should last for many years.

You can find both drainage pipe and PVC pipe at lumber yards or home improvement stores, as well as at some garden centers. The pipes come in lengths of between 3 and 10 feet and need to be cut before they can be used. 

PVC dust is nasty and hazardous, so if you decide to cut the pipes yourself, be sure to wear goggles and a mask and work only in a well-ventilated area, in addition to taking all the other precautions you would take when operating a saw.

You will want one deep watering pipe for each tomato plant to be transplanted. If you are using raised or prepared garden beds, the pipes should be 4″ longer than the depth of the bed. If you are planting tomatoes directly in the soil, the pipe should be about 16″ long.

How To Install Deep Watering Pipes In A Garden Bed

The ideal time to install the pipes is just before the tomato plants are transplanted into the bed. If you have already planted the plants, you must be very careful in digging holes for the watering pipes so as not to disturb the tomato roots.

If you are using beds one foot (12″) deep, then each pipe should be about 16″ long. This length will enable the bottom of the pipe to rest on the bottom of the garden bed and the other end of the pipe to stick up above the bed’s surface far enough to be easily watered.

After you have finished preparing the garden bed, dig two holes, one on either side of the spot where the tomato plant will grow. A posthole digger can help speed the process up considerably. 

Once the garden bed soil is removed, put a pipe into the hole, ensuring it is vertical and has good contact with the harder soil surface under the bed. Pack the bedding soil around the pipe firmly to hold it in place. Don’t put any dirt in the pipe itself.

Once the pipes are installed, you may then transplant the tomato plants. When you finish, you will end up with an alternating row of tomato plants and watering pipes. 

If you use a more intensive gardening method, in which the plants are laid out on a checkerboard, you simply start the next “row” with a plant next to the pipe of the first row and alternate.

Tomato Watering Tips: How Often To Water Using The Deep Watering Method

Tomatoes develop extensive root systems and need lots of water. You will need to give your tomato plants constant attention and be ready to practice a bit with watering to perfect your technique.


Before watering tomatoes, it’s important to check soil moisture first. To do this, push your finger into the dry soil about an inch or two.

At transplanting, the tomato seedlings need a good soaking when first placed in the ground. Given that they are quite small, it is probably sufficient to soak the ground around the plant. The root system of the seedling is not extensive enough to benefit from the deep watering pipe next to it.

Mulching your tomatoes is also important and should be done immediately after planting. Applying a layer of mulch will help grow robust plants with juicy tomatoes. Spreading organic materials, such as shredded leaves, grass clippings, straw, and peat moss, are preferred. Aside from organic mulch, you can also apply inorganic mulch, such as black or red plastic.

To transplant larger plants, you should also soak the ground around them directly. Once the tomato plants have grown larger, they will use water intensively and need more frequent watering. Also, tomatoes will require more regular watering during hot weather.

Make sure you have regular watering with sufficient water, as inconsistent watering can cause blossom end rot, root rot, cracked tomatoes, and stressed tomato plants.

Moreover, over-watered tomato plants will often look depressed and have yellow leaves that would turn brown around the edges. Other early signs of overwatered plants include cracked fruits and blisters on the lower tomato leaves.

Similarly, tomatoes will need less water, or none at all, after heavy rainfall storms have soaked the soil naturally.

Once the tomato plants begin to set fruit, the plants still require a steady supply of water. However, you must observe the plants carefully at this stage when watering. Excessive water will cause the tomatoes to split as they develop. Also, reducing the water slightly may enhance the flavor of the tomato fruit.

However, the tomato flavor may still depend on various factors, including variety, chemistry, and care, so it’s important to optimize these factors if you want the most flavorful tomato harvest possible.

When watering garden tomatoes, simply pour sufficient water into the pipe until it fills. It will drain away slowly into the soil and be available to all parts of the root system of the tomato plants next to it.

If you wish to add an occasional dose of liquid fertilizer, whether a natural tomato fertilizer or artificial, that can be added to the water and poured right in.

The general rule for tomatoes is that they should receive 1.5″ water per square foot of soil per week. Practically, it may be easier to think in terms of gallons rather than inches of water. This translates to about 1 gallon per week per square foot.

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