Learning how to grow tomatoes may feel overwhelming. Entire books have been written about growing tomatoes, but these 10 tips will fast-track you to tomato-growing success.
The taste of homegrown tomatoes is the reason many people begin a garden. In the United States, it is said that more gardeners grow tomatoes than any other vegetable.
Wondering about how to grow tomatoes in Arizona, the low desert, and other hot climates? Keep reading; there is plenty of information for you too!
Low desert includes elevations below 3500 ft in the Southwest, such as the Phoenix and Tucson metro areas.
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10 Tips for How to Grow Tomatoes
Tip #1 for Growing Tomatoes: Choose a tomato variety suited for your tastebuds and climate
Decide which type of tomato you want to eat. Different types of tomatoes are suited for eating fresh, canning, making salsa, or cooking.
For the best chance of success, choose a type of tomato suited to your climate. Because of the heat of Arizona summers, we have a short growing season. Look for plants with short (60-90) days to maturity. These are often types with small to medium fruit or Roma or paste varieties.
Varieties highly recommended for desert climates like Arizona include: Punta Banda, Celebrity, Pearson, Speckled Roman*, Black Krim*, Atomic Grape*, Sungold, Sweet 100, Yellow Pear, Canestrino*, and Cherokee Purple.
(* Local Master Gardener Carol Stuttard recommended varieties.)
Florida gardeners battle high heat and humidity. The Everglades tomato does well in those conditions.
Different climates have other considerations and growing conditions. Ask a local grower for varieties that do well in your area.
Tip #2 for How to Grow Tomatoes: Plant tomatoes at the correct time
To give tomato plants the best chance for success, plant tomatoes right after the last spring frost date. This is usually around February 15th – March for the low desert of Arizona. For this planting, start seeds indoors from December – January.
Once planted, if necessary, protect plants from cold nighttime temperatures. Plant tomatoes in the morning, so tomatoes have the day to settle in before cooler nighttime temperatures.
There is a second (monsoon) planting window for planting tomatoes in Arizona’s low desert from July through September. For this planting, start seeds indoors from May – July.
Once planted, protect plants from high daytime temperatures with a shade cloth. Plant tomatoes in the evening so tomatoes have a cooler evening to settle in before hot daytime temperatures.
Tomatoes grow best in temperatures of 70℉ to 90℉ with nighttime temperatures consistently above 55℉. In Arizona, you want tomatoes to flower and set fruit before it gets too hot. Once temperatures reach 90℉, tomato pollen is not viable. Fruit that has set will continue to mature, but new fruit will not set if pollen is not viable.
Tip #3 for Growing Tomatoes: Plant tomatoes in the right location
- The most important requirement for productive tomatoes is plenty of sunshine.
- Give tomatoes full sun for the entire plant with adequate growing space around each plant for air circulation.
- Allow 2 feet between each plant for healthy and productive plants.
- Do not plant tomatoes in the same location year after year. Rotate the location to prevent build-up of disease in soil.
Tip #4 for How to Grow Tomatoes: Prepare soil correctly
Tomatoes need soil rich in organic matter; make a habit of amending your soil with compost. Good drainage is important as an area with standing or puddling water invites disease. Prepare your soil correctly and your plants will thank you. If you are growing tomatoes in raised beds, this article talks about the best soil for raised beds.
Tip #5 for Growing Tomatoes: Plant tomato seedlings deeply
Planting deeply encourages a more extensive root system and a healthier plant.
- Remove the bottom 2/3 of leaves on the tomato transplant.
- Dig a shallow trench or deep hole (depending on depth of planting bed) and plant transplant so that only top leaves are above the ground.
- Roots will grow along the entire stem of the plant.
- Bear in mind that plants may appear to do nothing for a bit after planting the tomato- but they are growing roots.
Tip #6 for How to Grow Tomatoes: Mulch tomato plants well
Use compost, straw, leaves, or pine needles to reduce evaporation and insulate the soil from extreme hot and cold temperatures; soil will stay at a more even temperature.
Mulching helps control weeds, and plants will not have to compete with weeds for water and nutrients. Most mulch ultimately becomes fertilizer as it decomposes into the soil around the plant.
Tip #7 for Growing Tomatoes: Water tomato plants correctly
- Water early in the day to prevent excessive evaporation.
- It’s best to water at the soil level, so leaves do not get wet. Wet leaves encourage disease.
- Water to a depth of at least 12 inches to encourage roots to grow deep in the soil to find nutrients and moisture.
- Water slowly and deeply.
- Deep, extensive roots help plants withstand dry spells.
- Water regularly as needed, but do not allow plants to become soggy as plant roots need oxygen. How often you water depends on your soil and the weather conditions. Water deeply each time you water and then let the top few inches dry out before watering again. During the hottest months of the summer, that might mean every day. During the winter, that often means every 7-10 days.
Tip #8 for How to Grow Tomatoes: Feed tomato plants
When planting, if your soil is low in phosphorus it’s important to provide a source of phosphorus (bone meal or rock phosphorus) and again as plants begin to bloom and produce fruit. A soil test can determine if your soil is low is phosphorus. Without proper fertilization, plants do not produce well and are prone to weeds (which invite pests and other diseases).
Once tomatoes set fruit feed them about once a month. Tomatoes do best with regular feeding from organic sources of fertilizer. I feed mine with a diluted fish emulsion/seaweed fertilizer.
Tip #9 for Growing Tomatoes: Provide support for growing tomato plants
It’s important to encourage tomatoes to grow vertically.
- Growing tomatoes vertically keeps the plant upright, and prevents the stems from breaking from heavy fruit or wind.
- Trellising tomatoes also keeps the leaves off the ground which helps reduce diseases.
- Fruit is easier to harvest when it is off the ground as well.
Tip #10 for Growing Tomatoes: Provide shade for tomato plants in extreme climates like Arizona
Your plants may need a little help to get through a long, hot summer in the low desert of Arizona.
- Shade can reduce the air temperature for tomatoes by several degrees, and it also extends the growing season.
- Providing shade in desert climates helps reduce stress on tomato plants, and can prevent sunscald on ripening tomatoes.
- Shaded tomato plants are more likely to survive the extreme heat of the desert, and may perform better when cooler temperatures return in the fall.
Want more information about gardening in Arizona? This blog post shares 7 tips for how to grow a vegetable garden in Arizona.
Tuesday 18th of April 2023
I have three tomato plants that are growing and two have gotten a blossom or two but no fruit is growing... is there something special I should know about pollination or do you think it might be something else? They appear to be healthy...
Tuesday 18th of April 2023
Hopefully soon! The weather has been a little wacky this year. You can tickle the blossoms to encourage fruit set.
Tuesday 28th of March 2023
I'm a beginner and have found you to be extremely helpful, I'm located In Tucson and I just started my seeds 3/25/23, they are cherry tomatoes, did I start them too late?
Tuesday 4th of April 2023
It's been a crazy year. It might be too late, it depends on how quickly it gets hot. You may want to look for transplants as well.
Thursday 9th of March 2023
Hi Angela So Happy to find your channel on you tube I live in Vail AZ outside Tucson which appears to be zone 8B or 9A. I have no idea how to know which is accurate. I am trying to grow tomatoes in elevated planters. I believe my last frost date is later than yours. Any advice on how to translate your low desert advice to my location? I am most interested in what direction I should orient the planters for best results. Also how do you feel about cedar elevated planters with self watering trays in the bottom of the planting box
Look forward to your response
Saturday 11th of March 2023
Use the last frost date as a guide for when to plant your tomatoes https://www.almanac.com/gardening/frostdates Choose a location with morning sun and afternoon shade. Elevated containers will heat up more than those on the ground. The self-watering trays are helpful for watering.
Thursday 14th of July 2022
Tip 7 states to water regularly. How often is that in Arizona. I am used to gardening in Utah. Tip 8 says to feed plants every 2-3 weeks, what do you feed them with?
Tuesday 19th of July 2022
How often you water depends on your soil and the weather conditions. Water deeply each time you water and then let the top few inches dry out a bit before watering again. During the hottest months of the summer that might mean every day. During the winter that often means every 7-10 days. I feed my plants with diluted fish or seaweed fertilizer.
Sunday 3rd of July 2022
Your site is absolutely wonderful. So informative and easy to follow. I have a some questions from an old gardener but from the East Coast. In Ma. we had a small farm and grew wonderful vegetables. Fast forward I moved here in Sept. 2020 and last year with a friend tried to grow tomatoes, pole beans, cucumbers inside in the AZ. room. I can't garden outdoors, I'm in a rental house in Sun City West and the yard is all ornamental rocks. The Az. room is East facing in the morning and the sun shifts to the West in the afternoon. I started with seeds and after the 2nd set of leaves started taking them out onto to the patio. I would take them out at 6am and bring them back in between 9 and 10 am, didn't know then what to plant and not to and the 3 separate growing seasons. Then the gnats hit and I lost everything before the plants were even 6 inches tall. So I gave up for the season after cleaning every pot and discarding the soil. I have since read some info. from the State and decided to try again. In April this year, we started and the seeds took off like gang busters giving me hope. Then the plants started to stagnate and stopped growing. The gnats even returned and I did not put any plants outdoors at all. All the plants were set 1 feet back from the windows and when they started to have burned leaves we moved them to 3 feet back. Now they are stagnate again even the geraniums are losing their green and some leaves are turning light green. I have 4 tomato seedlings that are still alive and are still 4 inches tall, darnest thing I've ever seen. I would love some help, I am determined to grow some veggies again. You can call me also. Thanks and have a great 4th.
Monday 4th of July 2022
Hi. If they stop growing they may need larger containers or more nutrients. This blogpost may help: https://growinginthegarden.com/when-and-how-to-pot-up-seedlings/