Planting Guides

When to Plant Tomatoes in Salt Lake City: Complete Guide + Best Varieties for Zone 7a

Salt Lake City, Utah

USDA Zone 7a

Last Frost: Apr 25

Last updated: October 30, 2025

Plant tomatoes in Salt Lake City from May 1-8 after the last frost (April 24). This comprehensive guide covers the best varieties for Utah's high desert climate.

DDorothy "Dot" Williams

October 30, 2025

Tomato plants growing in Salt Lake City garden with mountain backdrop showing ideal planting conditions — — Image © PlantReference.org 2025

Quick Answer

Plant tomato transplants in Salt Lake City from May 1-8 after the last frost date of April 24. Choose heat-tolerant varieties like Solanum lycopersicum 'Early Girl' for best results.

TL;DR

Plant tomatoes in Salt Lake City from May 1-8 after the last frost date of April 24. Zone 7a conditions with 173 growing season days allow excellent harvests. Best varieties include Solanum lycopersicum 'Early Girl', Solanum lycopersicum 'Stupice', and Solanum lycopersicum 'Cherokee Purple' for Salt Lake City's high desert climate and temperature swings.

Product Recommendations

XLUX Soil Moisture Meter T10

($9-12)— Essential for managing watering in Salt Lake City's low humidity conditions

XLUX Soil Moisture Meter T10 Bonsai Moisture Testing Kit

https://www.amazon.com/XLUX-Moisture-Testing-Bonsai-Houseplant/dp/B014MJ8J2U

This affordable moisture meter features a 10-inch probe that reaches deep into Salt Lake City's clay-heavy soil to measure root zone moisture levels. No batteries required—simply insert and read instantly. The extended probe length is crucial for Utah's deep-watering needs, helping prevent both drought stress and overwatering that leads to blossom end rot. Durable construction withstands repeated use in rocky desert soils.

Price: $9.99-$12.99

Espoma Organic Tomato Tone

($12-15)— Formulated for consistent feeding in alkaline soil conditions

Espoma Organic Tomato Tone Natural Plant Food 4 lb

https://www.amazon.com/Espoma-TO4-4-Pound-Tomato-tone-3-4-6/dp/B002L9U6SS

This organic fertilizer blend contains beneficial microbes and slow-release nutrients specifically balanced for tomatoes. The 3-4-6 NPK ratio provides steady nutrition without excessive nitrogen that causes leafy growth at the expense of fruit. Includes calcium and magnesium to help prevent blossom end rot common in alkaline Utah soils. The organic formulation improves soil structure while feeding plants, essential for long-term soil health in desert conditions.

Price: $12.49-$15.99

Agribon+ AG-19 Floating Row Cover

($18-25)— Protection from late frosts and wind damage

Agribon+ AG-19 Floating Row Cover 10x25 feet

https://www.amazon.com/Gardens-Alive-Agribon-Floating-Cover/dp/B00QFHQ8YE

This lightweight spun fabric provides 4-6°F frost protection while allowing 90% light transmission, perfect for Salt Lake City's unpredictable spring weather. The breathable material prevents overheating during warm days while protecting against wind damage common in valley locations. Easy to install over hoops or directly on plants. Reusable for multiple seasons and effective against early insect pests. Essential insurance for protecting transplants during temperature swings.

Price: $18.99-$24.99

Rain Bird Drip Irrigation Kit

($35-45)— Critical for consistent watering in low humidity conditions

Rain Bird 32-Plant Drip Kit for Container and Raised Bed Gardens

https://www.amazon.com/Rain-Bird-32ETI-Irrigation-Container/dp/B00L5IASLY

Complete drip irrigation system delivers water directly to root zones, essential for managing tomatoes in Salt Lake City's rapid-evaporation conditions. Kit includes timer, pressure compensating drippers, and tubing for 32 plants. Precise water delivery prevents the moisture fluctuations that cause blossom end rot and fruit cracking. Reduces water waste by 50% compared to overhead watering while keeping foliage dry. Simple installation with no digging required.

Price: $35.99-$44.99

Dalen Gardeneer Tomato Cage

($15-20)— Heavy-duty support for high winds and large plants

Dalen Gardeneer Square Folding Tomato Cage 54 inches

https://www.amazon.com/Dalen-Gardeneer-Folding-Tomato-Cages/dp/B01MQPQRB8

Heavy-duty steel construction withstands Salt Lake City's strong winds that can destroy lighter cages. Square design provides more growing space than round cages, important for indeterminate varieties like Cherokee Purple. Folds flat for storage and features vinyl coating that resists rust in Utah's mineral-rich water conditions. 54-inch height accommodates vigorous growth while multiple horizontal supports prevent stem damage from wind movement.

Price: $15.99-$19.99

Frequently Asked Questions

When is the last safe date to plant tomatoes in Salt Lake City?

June 15 is the latest you should plant tomatoes in Salt Lake City to ensure harvest before the October 14 first frost. This allows approximately 120 days for varieties like Solanum lycopersicum 'Early Girl' to mature. Later plantings risk losing fruit to frost, especially for longer-season varieties like Solanum lycopersicum 'Brandywine' that need 80-100 days.

Why do my tomatoes get sunscald in Salt Lake City but not other places?

Salt Lake City's 4,226-foot elevation means 25% more intense UV radiation than sea level locations. Combined with Utah's clear, dry air that doesn't filter UV, tomato fruit literally burns when directly exposed to afternoon sun. Maintain leaf cover over developing fruit or use 30% shade cloth during the hottest part of summer. Varieties like Solanum lycopersicum 'Cherokee Purple' show better UV tolerance.

Should I grow tomatoes from seed or buy transplants in Salt Lake City?

Buy transplants for your first season while learning Salt Lake City's unique growing conditions. The 6-7 week indoor growing period requires managing Utah's intense spring sun during hardening off. Start your own seeds in subsequent years using varieties adapted to local conditions. Open-pollinated varieties like Solanum lycopersicum 'Stupice' improve when seed is saved from plants that thrive in your specific microclimate.

How do I prevent blossom end rot in Salt Lake City's alkaline soil?

Blossom end rot is extremely common here because alkaline soil (pH 7.5-8.5) interferes with calcium transport to developing fruit. Maintain consistent soil moisture with drip irrigation and heavy mulching. Don't cultivate near plants once fruiting begins—root damage disrupts calcium uptake. Add sulfur to gradually lower pH over time, making calcium more available to plants.

What's the biggest mistake new Salt Lake City tomato growers make?

Planting too early without protection from temperature swings. New gardeners see the April 24 average last frost date and plant immediately, but Salt Lake City's elevation creates dramatic day-night temperature differences that shock young plants. Wait until May 1-8 and use season extension tools like Wall O' Water or cloches for the first two weeks. This prevents the purple foliage and stunted growth that delays harvest by weeks.

Can I grow heirloom tomatoes successfully in Salt Lake City?

Yes, but choose heat-tolerant heirlooms and provide extra care. Solanum lycopersicum 'Cherokee Purple' originated in hot climates and adapts well to Utah conditions. Solanum lycopersicum 'Brandywine' is more challenging but possible with afternoon shade and excellent soil preparation. Avoid heavy pruning that exposes fruit to intense UV, and be diligent about consistent watering to prevent blossom end rot.

How late can I harvest tomatoes in Salt Lake City?

Salt Lake City's long, warm autumn allows harvesting into mid-October, often until the first hard frost around October 14. The stable fall weather and intense sun create excellent ripening conditions. Harvest mature green tomatoes before first frost—Utah's low humidity provides ideal indoor ripening conditions that can extend fresh tomatoes into December.

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Tagged with

#salt lake city gardening #zone 7a tomatoes #utah vegetable gardening #high desert gardening #alkaline soil tomatoes #mountain west gardening #tomato planting dates #early girl tomatoes #cherokee purple utah #stupice tomatoes

Written By

Dorothy "Dot" Williams

Dot grew up on a small farm in rural Virginia and has maintained a vegetable garden for decades. After retiring from teaching elementary school, she became a Master Gardener volunteer and spends her time mentoring new gardeners at community garden plots in Richmond. She's especially knowledgeable about heirloom varieties, seed saving, and traditional growing methods passed down from her grandmother. Dot's no-nonsense advice comes from extensive trial and error—she's seen every tomato disease, pest problem, and weather disaster imaginable. Her biggest pet peeve is gardeners who overcomplicate simple tasks. "Plants want to grow," she often says. "Your job is to not get in their way."