In the second part of our tomato series, we discussed fertilization and weed control. In this edition, we will talk about two important parts of growing tomatoes, planning the garden layout and the thing we seem to either have too little or much of, water. Water is a critical resource in everything we do as humans. Sufficient water is the key to success in our gardens. I’d also like to share a photo from my 2019 tomato season, my daughter helping me with planting our garden (Photo 1). I must insist that eating the garden dirt would be an unpleasant experience, but she disagreed. We had so much fun planting the tomatoes, watching them grow, and learning to walk as she quickly needed to inspect our plants daily.

PLANTING
Garden layout
It is best to plan the planting arrangement and measure distances between rows and plants ahead of time. The distance between plants in the row (in-row spacing) depends on the type of tomatoes being grown and the pruning methods that will be used. Determinate varieties do not grow as tall as indeterminate and can normally be spaced closer in the row. Gardeners can chose to plant at a wider in-row spacing to allow easier access. Pruning will be discussed in detail below and is commonly used to manage growth in indeterminate tomatoes. Between- row spacing can be related to the type of tillage equipment being used and can be wider if needed. Keep in mind, though, that wider plant and row spacing will also mean more space open for weed growth.
When choosing a site, it is best to choose a location that receives morning sun and afternoon sun. Morning sun will dry the plants’ leaves and stems from overnight dewfall and/or rain. Moisture can promote bacterial and fungal growth on tomato plants. Soil moisture is good, moisture on the leaves and stems can lead increased disease.

Planting techniques
When soil is properly prepared and the threat of spring frost is passed. There is a 10% chance of frost after April 28th in Union County using the last 30 years of weather data from the NOAA. Tomato transplants can be planted in the garden. Young plants should be around 6 to 10 inches tall and properly hardened off at transplanting. In well-prepared soil, a hole is dug deep enough to cover the root ball of the plant. If transplants have been grown in fibrous containers that are planted rather than removed, make sure that all parts of the container are covered with soil to prevent water loss from exposed edges. Often, a soluble starter fertilizer will be added to the planting hole to provide moisture and nutrition for the young transplant.
Tall, leggy plants are a challenge in the home garden. It may be best to install the support system at planting to support the tall plants and plant them at a normal depth. Stems closest to the ground should be pruned off. Removing the lower stems reduces contact of the plant’s leaves to the soil, which will possibly prevent disease transmission.
Some gardeners make a trench to lay a portion of the stem horizontally under the soil or they bury the plant extra deep. While roots will emerge from these buried stems, such practices can lead to stem breakage or lower soil temperature, aeration or nutrients for the deeply planted roots. Additionally, both of these practices will negate the impact of grafted rootstocks if grafted plants are used. The best practice is to select and plant healthy and appropriately sized tomato plants.

WATER MANAGEMENT
For best growth, keep the soil in the root zone moist enough to prevent wilting of tomatoes. This is especially important soon after transplanting when the plant is transitioning to garden conditions. Garden tomatoes will generally require 1 to 1.5 inches of water per week, but this number can change according to environmental conditions and plant size. Managing water in garden tomatoes is based on knowing the rainfall received on your site and then applying water if rainfall is not sufficient. Rain gauges and weather tracking can help you determine how much to water to apply.

One major contributing factor to disease in tomato plants and all vegetable plants is moisture. The soil needs to be moist, not the leaves and stems. Moisture on the leaves and stems will increase bacterial and fungal disease of tomato plants. Water applied to tomatoes using sprinklers will cause more disease issues. Additionally, more water will be required to provide sufficient moisture to the soil using a sprinkler than soaker hoses and drip irrigation. Soaker hoses can be cost-effective and versatile in the garden, but they do not deliver water as evenly as drip irrigation lines. If sprinkler irrigation is the only option, apply at a time when leaves will dry before nightfall to lower the risk of leaf disease.

Most years in Tennessee there will be periods of the spring, summer and early fall when rainfall is insufficient or inconsistent for the best tomato plant growth. Tracking the volume over the season will help make irrigation practices more precise. When irrigating, it is best to apply 1/2 to 3/4 inch of water twice a week rather than the full amount in one irrigation event. This will reduce runoff and provide more consistent soil moisture but provide enough water to wet the soil for several inches. Likewise, it is best to deliver irrigation to the root zone of the plants through trickle or drip irrigation rather than overhead watering. Drip irrigation will be more efficient in water use and will keep the plants leaves dry. Soaker hoses are also common in the home garden and deliver water directly to plant roots. They can be purchased or constructed from used garden hose.

In the next article, we will discuss plant management, support, and pruning. For more information, please contact Shannon DeWitt, UT Extension Union County (865) 992-8038 or sdewitt@utk.edu

Written by Extension Agents: Shannon Dewitt, Anthony Carver, & Natalie Bumgarner