Tomato - Planting/Growing/Harvesting
Yavapai County Cooperative Extension
Before working the soil, make sure that it is not wet. It should crumble between your fingers. Add a generous dose of compost (hopefully homemade) and a small amount of nitrogen fertilizer. Excessive nitrogen results in lots of foliage and limited fruit. If you have soils developed from limestone, add a small amount of soil sulfur too. Spade this in to a depth of one foot and mix it well. Then you may remove a shovelful of soil and place a small amount of triple super phosphate (0-45-0) at a depth about 3 inches below the where the root ball will be planted. Phosphorus is not mobile in the soil, so placing it below the root zone maximizes its availability. Bone meal and rock phosphate also contain phosphorus, but these products are not as readily available to the plants.
After the soil is prepared, it’s time to plant. Individual tomato plants should be planted at least 24 inches apart. Plant the transplant slightly deeper than it had been growing in the container. Pinch off the bottom leaves of tall, spindly transplants and lay the stems sideways in a trench. Carefully bend the stem upward so that the upper few inches of stem are above the soil surface. Roots will develop all along the buried stem. Pack the soil loosely around the plant. Water the tomato plants slowly and deeply to get them off to a good start. If there is a potential for frost, place a Wall O’ Water over the plant and gently fill it with water. Some people use a five-gallon bucket with the bottom cut out to support the Wall O’Water while filling it.
Growing in Containers
There are some particular challenges to growing in containers. Variety is important. You can grow patio tomatoes, determinate tomatoes and indeterminate tomatoes in containers. Each need successively larger containers. Indeterminate tomatoes have extensive root systems and very, very long vines making them difficult to grow unless the container is large. Patio tomatoes have been developed to be small plants and do well in containers. Determinate are the middle child, bigger than patios, smaller than indeterminates. Match the container to the type of tomato.
Use a good potting mix with compost—it needs to drain well. You don’t want a soggy soil. Watering is critical. Find the sweet spot of not too much and not too little. Try not to let the soil cycle from very wet to very dry, even watering is the key. A drip system with a timer controlling the watering schedule is recommended. Even with that you need to keep an eye on them. Containers tend to accumulate salts in the soil and need to be flushed occasionally to remove it. Irrigation timers need attention. Just when you stop paying attention, they will stop working, need new batteries or the drippers will clog up. Check periodically to make sure everything is working. If you are watering by hand, water thoroughly to get moisture throughout the pot and flush out salts. Don’t let it dry out completely. Containers need to be fertilized more often but use light applications (approximately ½ the amount recommended) more often. Using a time-release fertilizer will also work.
Tomatoes are warm season vegetables. If you plant before the danger of frost is past, you must use a method of frost protection. The Wall O’Water works well. These transparent plastic devices are about $3 each and consist of vertical sleeves that hold water and protect plants from frost damage. The water absorbs heat during the day and reradiates it at night. The Wall O’Water also protects the tomato plant from drafts.
To Stake, or Not
Some folks prefer to tinker with their garden and manipulate tomato plants by staking them or using cages. Others allow the plants to sprawl every which way across the soil surface. It really doesn't matter which you do; fruit production will be roughly the same either way. On the ground, you may lose some fruit to rot and insect damage. Staking can save space but will also expose the plant to wind and sap some energy to support the vines.
To Shade, or Not
Tomatoes need 6 to 8 hours of full sun for the best production. With too little sun they will get leggy and flower less. Too much sun and the tomatoes may sunburn. The best shade level is 20 to 40% shade. Most of the shade cloth that is sold locally is rated at more than 40% but you can find more open versions online. Even with our heat, the whole plant doesn’t have to be shaded. Fruit can be ruined by sunburn. A plant that is healthy and growing well creates enough leaf cover to protect the tomatoes from the sun. If you have a scraggly plant with poor leaf cover for the fruit, you might want to come up with a creative way to shade the plant just during the hottest part of the day.
To Prune, or Not
There seem to be endless emotional arguments about pruning tomatoes. Tomatoes don’t require pruning. Pruning is designed to improve the amount of sun a plant gets and create healthy strong vines. It can improve a plant that has grown too large and is probably more important when growing indeterminate tomato plants in a greenhouse. In Arizona lots of leaves help protect the fruit from sunscald.
At the end of the growing season, pick all green tomatoes before the first killing frost. These will ripen indoors when stored in a cool moist place.
Return to Yavapai Edibles page.