Cherry tomatoes are a popular choice for home gardeners, known for their abundant harvests and sweet, bite-sized fruit. These flavorful tomatoes are particularly well-suited for small spaces and container gardening, making them accessible even for those with limited outdoor area. Starting cherry tomatoes from seed allows for the greatest selection of varieties and ensures you have healthy, vigorous plants ready for the growing season. This guide provides a complete, step-by-step process for successfully growing these prolific plants.
Selecting Seeds and Timing
Choosing the right type of cherry tomato seed is the first step, deciding between determinate and indeterminate varieties. Determinate tomato plants grow to a fixed, bush-like height, often around three to five feet, and produce their fruit within a short, concentrated period. These compact plants are an excellent choice for containers or smaller gardens where space is limited and are easier to manage without extensive support structures.
Indeterminate varieties, however, grow as vines and continue to lengthen, flower, and produce fruit until the first hard frost, offering a continuous harvest throughout the entire season. While they require strong staking or caging and more management, they provide a much greater overall yield. The correct time to sow is determined by counting back six to eight weeks from your region’s average last expected spring frost date. This calculation ensures the seedlings are mature enough to be transplanted outdoors when the weather is consistently warm, preventing leggy, overgrown plants indoors.
Starting Seeds Indoors
To begin the indoor process, a sterile seed-starting mix is necessary, as garden soil can compact and harbor pathogens that harm delicate seedlings. Fill a seed tray or individual pots with this moist mix and sow the small tomato seeds about one-quarter of an inch deep. The ideal environment for germination is a consistently warm temperature, optimally between 70 and 85 degrees Fahrenheit, which is most reliably achieved using a seedling heat mat placed beneath the tray.
After planting, cover the trays with a clear dome or plastic wrap to maintain high humidity, which helps promote quick sprouting. Once the first tiny seedlings emerge, typically within five to ten days, the heat mat must be removed, and the plants need immediate, intense light exposure. Placing the seedlings under a dedicated grow light for at least 14 to 16 hours daily is essential to prevent them from stretching toward a distant window light, a condition known as etiolation. Maintaining cooler air temperatures, between 60 and 70 degrees Fahrenheit, while providing strong light encourages a stocky, resilient plant structure.
Transplanting and Outdoor Establishment
Before moving the pampered seedlings into the garden, they must undergo a slow acclimation known as “hardening off,” which toughens them against the harsher outdoor elements like wind, direct sun, and temperature fluctuations. This process should take place over seven to fourteen days, beginning with placing the plants in a sheltered, shady outdoor location for just one to two hours per day. Gradually, the duration of outdoor exposure is increased, including slightly longer periods of gentle sunlight and wind, until the plants can tolerate a full day outside.
The final transplanting should only occur when all danger of frost has passed and nighttime temperatures are reliably above 50 degrees Fahrenheit. Tomato plants are unique because they can generate new roots along any part of their stem that is buried beneath the soil. To leverage this ability and encourage a strong root system, strip the leaves off the lower two-thirds of the stem and plant the seedling deeply into the ground or container, burying the stem up to the first set of remaining leaves. This deep planting technique helps the plant establish a robust foundation capable of supporting a heavy fruit load.
Ongoing Care and Harvesting
Once established outdoors, consistent care focuses on managing water, nutrients, and physical support to maximize the harvest. Tomato plants require consistent moisture, particularly those in containers, so watering slowly and deeply at the base of the plant is preferred to avoid splashing water onto the foliage, which can encourage fungal diseases. Proper nutrition is also necessary, starting with a balanced fertilizer, but transitioning to a formula with less nitrogen and higher phosphorus and potassium once flowering begins to encourage fruit production over excessive leafy growth.
Since nearly all cherry tomato varieties, especially the high-yielding indeterminate types, grow tall and heavy, a support system must be installed early to prevent the main stem from snapping. This support can be a sturdy tomato cage, a stake, or a trellis, which should be placed at the time of transplanting to avoid damaging developing roots later. Harvesting should occur when the tomatoes achieve their full, vibrant color and separate easily from the stem with a gentle twist. Picking the ripe fruit regularly encourages the plant to continue setting new flowers and fruit, ensuring a continuous supply of sweet cherry tomatoes until the season concludes.