Planting time for tomatoes varies both by region and by cultivar. You do not need to be a slave to nature, however, as there are numerous adaptations you can make to your growing conditions to work with your climate and achieve a successful season with this popular garden plant.
General Guidelines
For climatic zones where frost is a concern, the general recommendation is usually to start seedlings indoors about six weeks before the last frost date, and to transplant seedlings to the garden two to four weeks after the last frost. To determine the optimal time for your area, check your USDA planting zone for anticipated frost dates.
Other signs that it is planting time for tomatoes include the following:
- Lilac blossoms are dwindling, and lily-of-the-valley and flowering dogwood are in full bloom.
- The soil temperature measures more than 55 degrees Fahrenheit (13 degrees Celsius) three mornings in a row using a soil thermometer.
- The last full moon of late May or early June has passed, and the moon is in its second quarter.
Factors Affecting Planting Time for Tomatoes
Climate
Tomatoes are essentially a sub-tropical plant. They are naturally adapted to grow on cool, misty mountain slopes where they are sheltered from extremes of heat and cold. If you live in a cooler climate, you will need to make adaptations to lengthen your growing season if you want to see your tomatoes bear usable fruit.Very hot climates pose a different sort of problem. While tomatoes generally do well in warm climates, they do not produce pollen at temperatures that average more than 85 degrees Fahrenheit (about 30 degrees Celsius). If you live in an area where daily highs regularly soar above this level, you will need to alter planting time to work around the hottest part of the season.
Cultivar
Tomatoes are one of the most popular garden plants, and even gardeners who grow no other vegetables will often have a tomato vine or two in a patio container or tucked away among the flowers. Due to the tomato's popularity, gardeners have worked to develop cultivars that are well adapted to nearly every growing condition, from the intense heat of a Florida summer to the chilly threats of a Siberian frost. Choosing a cultivar that is well adapted to your climate will give you more flexibility in when you plant your tomatoes.Cultivars that do well in cooler environments include:
- Black Krim
- Stupice
- Siberian
- Glacier
Cultivars that are tolerant of heat extremes include:
- Porter's Pride
- Heatwave
- Solar Set
Microclimate
While USDA gardening zones give a general indication of planting opportunities and limitations for your region, a good microclimate can often give you some wiggle room within these guidelines. A sunny, sheltered location such as a south-facing wall or fence can support plants that would normally only grow outside of your planting zone.
Working with Your Environment
Cold Climates
In regions where cold is the limiting factor, there are a few steps you can take to alter planting time for tomatoes and get a few more weeks out of the growing season. To work with a frosty climate, try the following adaptations:
- Protect seedlings using hot caps, wall-o-waters, or a cold frame.
- Use raised beds for your tomatoes and mulch with black plastic to increase soil temperature early in the season.
- Plant in trenches rather than holes. Cooler soil temperatures can hinder root formation. Laying as much of the seedling's stalk as possible along a trench makes more surface area available for root development.
- Consider a container garden. Tomatoes will do fine in pots or hanging baskets and you will be able to take them safely indoors when there is danger of frost.
- In very cold climates, a greenhouse may be the safest and most reliable environment for growing tomatoes.
Hot Climates
In climates where intense summer heat can prevent pollination, you can adjust tomato planting time to work around the heat and humidity that can deter pollination and encourage bacterial and fungal growth. By treating the growing season as two short growing periods, you and your garden can both relax during the hottest part of the summer.To employ this method, choose determinate tomato cultivars. These plants have a shorter growing season, and carry out pollination and fruit production within a single, short time frame.
- Spring Tomatoes: Start seed in January to have well-developed seedlings available for planting at the very earliest opportunity in the spring.
- Autumn Tomatoes: Start seedlings indoors during the late spring or early summer, and plant in the vegetable garden as soon as the hottest part of the summer has passed.
There is simply no match for the flavor and quality of home grown tomatoes. By adjusting planting time and choosing a suitable cultivar, you should be able to enjoy the fruits of your own labor no matter what your climate.
