Ensure your new tomato plants thrive by planting seeds and seedlings at just the right time. Plus, learn how to check for ideal weather and soil temperatures.
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Knowing when to plant tomatoes is the key to a good harvest. These tender, heat-loving plants require warm temperatures and plenty of sunlight; they are susceptible to cold temperatures and frost. While the ideal planting time for tomatoes depends on where you live and your weather conditions, there are a few guidelines to follow.
The first rule of planting tomatoes in your garden is to wait until all danger of frost has passed and air and soil temperatures have warmed sufficiently. If youre learning how to grow tomatoes, then its vital to understand that planting them too early will not make an earlier-producing tomato. Rather, it exposes the tomato plant to late frosts, which could kill it.
For many gardeners, the ideal time to plant tomatoes is in late spring, but dont rush to get them planted before making some key checks first.
Growing juicy, flavorful tomatoes starts with getting the soil temperature right. As heat-loving plants, tomatoes need warm soil temperatures to thrive at every stage – from germinating seeds to ripening fruit. By optimizing soil warmth throughout the season, you’ll be rewarded with sweeter, more abundant tomatoes.
Why Soil Temperature Matters for Tomatoes
Tomatoes require warm soil to grow vigorously and produce a robust harvest Cool soil below 60°F causes problems like
- Slow, uneven germination of seeds
- Stunted growth when transplanting seedlings
- Poor flowering and fruit set
- Delayed maturity and flavor development
Maintaining the ideal soil temperature in the 65°F to 85°F range allows tomatoes to progress smoothly through each phase of development. Here’s an overview of tomato plants’ soil temperature needs:
- Seed Germination – 70°F to 85°F for fast, uniform sprouting within 6-8 days.
- Transplanting – 65°F minimum, ideally 70°F overnight. Prevents shock.
- Flowering & Fruit Set – 65°F to 80°F for prolific blossoms and pollination.
- Ripening – 70°F to 85°F for even maturity and full flavor.
Pay close attention to soil temperature at the actual planting depth, checking daily with a soil thermometer. Adjust your planting schedule and techniques to keep the soil in the optimal temperature window.
Target Soil Temperature Ranges for Tomatoes
To gain a full understanding of tomatoes’ soil temperature preferences, let’s take a closer look at each growth stage:
Seed Germination – 70°F to 85°F
For robust tomato seed germination, aim for soil temperatures between 70°F and 85°F. At these warm temperatures, seeds should sprout within a week. Cooler soil causes erratic, delayed germination taking 4-6 weeks at 50°F.
Seeds fail to emerge at all below 50°F and above 104°F. Use heating mats when starting seeds indoors to maintain ideal warmth.
Transplanting – 65°F to 80°F
Hold off transplanting tomato seedlings until daytime soil temperature is minimum 65°F, preferably 70°F and higher Nighttime lows should remain above 55°F
If soil is too cold, seedlings suffer transplant shock, showing stunted growth Maintain active root growth with adequately warm soil Row covers can provide extra warmth.
Flowering & Fruit Set – 65°F to 80°F
For prolific blossoms and successful pollination, tomato plants need soil temperatures between 65°F and 80°F. Shoot for nighttime lows above 55°F and daytime highs from 75°F to 85°F.
Extreme heat above 90°F disrupts pollination and causes flowers to blast. Provide shade and ample moisture to cool overly hot soil.
Ripening – 70°F to 85°F
Tomatoes require consistent 70°F to 85°F soil to ripen evenly with full flavor. Cooler temperatures delay maturity and affect taste.
Monitor soil moisture as well for proper fruit fill. Mulching moderates optimal warmth and moisture levels.
Adjusting for Regional Climate Conditions
When determining planting time, consider your local climate. In cooler areas, start seeds early indoors and use season extending covers. Wait for 55°F+ nights before transplanting.
In hot climates, provide shade and wind protection. Water deeply, and mulch to moderate soil temperature. Choose heat-tolerant varieties like Sun Master and Solar Fire.
The microclimate around your garden impacts temperature too. South facing beds warm faster while shaded gardens stay cooler in summer. Group tomatoes accordingly.
Tips for Controlling Tomato Soil Temperature
Here are some techniques for achieving ideal tomato soil temperature:
- Use black or red plastic mulch to absorb heat.
- Install cloches, low tunnels, or row covers to retain warmth.
- Mulch beds to stabilize soil temperature.
- Provide temporary shade covers during hot afternoons.
- Water early to prevent severe midday heat.
- Position plants to take advantage of sun/shade patterns.
- Select disease-resistant, heat-tolerant varieties as needed.
- Check soil temperature daily at 4 inch depth and adjust as needed.
Careful monitoring and adaptive gardening practices will maintain the properly warm soil tomatoes need from seed to harvest. Paying attention to temperature optimizes growth and results in your most bountiful tomato crop yet.
Ideal Soil Temperature for Planting Tomatoes
Soil temperature is another indicator of readiness. Planting in cold soil can result in generally stunted growth and nutritional deficiencies. Wait to plant tomatoes until soil temperatures have warmed to at least 60°F (16°C) – but ideally 65 to 70°F (18 to 21°C).
A quick and easy way to tell if the soil is warm enough for planting tomato plants is to thrust a finger in the soil. If you cannot keep your finger all the way in the soil for a full minute without feeling uncomfortable, the soil is most likely too cold for planting tomatoes. Of course, a soil thermometer helps too. ( credit: Getty s)
When to Plant for Your Area
Tomatoes are warm-season crops that grow in the spring and summer, with fruit production from summer to early fall, depending on the variety and your climate.
In warmer regions, tomatoes can be grown nearly year-round. Try planting tomatoes early in the spring and then again plant a second late-season crop of tomatoes in July to August.
- In the South, tomatoes can be planted in January for an April and May harvest.
- In the mid-Atlantic and similar climes, tomatoes can be planted in the spring for a late spring to early summer harvest.
- In the Pacific Northwest, tomatoes can be planted in late spring and harvested in the summer months.
- In the Northeast and into the Midwest, tomatoes are best planted late spring to early summer and harvested in midsummer through the first fall frost.
Bear in mind some tomato varieties are more cold-hardy than others. The number of days to maturity often listed on the seed packet will guide you as to whether a particular variety is suited for your area.
Importance of Checking Soil Temperature Before Planting – Quick Tip
FAQ
What is the best soil temperature for tomatoes?
The second sign for knowing when do you plant tomatoes is the temperature of the soil. Ideally, the soil temperature for the best time for planting tomatoes is 60 F. (16 C.). A quick and easy way to tell if the soil is warm enough for planting tomato plants is to thrust a finger in the soil.
Will tomato plants be ok in 40 degree weather?
Tomatoes can tolerate temperatures as low as 32°F, but thrive in temperatures above 50°F.
What temperature do tomatoes like at night?
Tomatoes require a minimum of six hours of direct sun daily. They prefer daytime temperatures of 70 to 80°F degrees and nighttime temps above 60°F.Jul 5, 2023
How often should I water tomato plants?
Tomato plants typically need 1 to 2 inches of water per week, but the exact frequency depends on factors like soil type, weather, and plant size.