I don’t know a single vegetable gardener who doesn’t have a few tomato plants (Solanum lycopersicum) in their garden. I’ve even heard that tomatoes are more popular in the home garden than any other vegetable in the world!
Tomatoes are great because they’re delicious, versatile, and relatively easy to grow. Whether you’re looking to take your tomato-growing game to the next level or are thinking about starting your very first plant this year, let me walk you through the stages of tomato plant growth that you can expect to see in the garden.
Conditions for Growing Tomato Plants
Tomatoes are warm-season vegetables that have no tolerance for frost. While tomatoes are grown as annuals in the vast majority of home gardens, they’re actually tender perennials that can live for several years in USDA zones 10 and 11.
In most climates, tomatoes are decidedly a summer crop. For zones 10 and 11, the peak tomato season is in the fall or winter.
Full sun is a must for growing healthy tomatoes. Plants should receive 8 to 10 hours of direct sun per day. But you may want to offer some shade during the hottest part of the day if you live in a warmer climate.
Tomatoes need about 2 inches of water per square foot weekly during the growing season. I recommend watering in the morning and using something like a soaker hose to keep the foliage dry — damp foliage is a breeding ground for pathogens.
Tomatoes are heavy feeders that respond well to soil amended with aged compost. Throughout the growing season, use a slow-release fertilizer with low to moderate nitrogen, such as a 3-4-6 or 9-4-12 formula. Per the University of New Hampshire, tomatoes thrive in slightly acidic soil with a pH of 6.2 to 6.8.
In my experience, a big part of what makes tomatoes so popular is that you can grow them in several different ways. You can easily fill a traditional garden bed with large cultivars for canning. But you can also grow a handful of tomato plants in a raised bed or a single plant in a 10- to 20-gallon container.
You can even grow individual tomato plants indoors in a warm, well-lit location like a heated sunroom or makeshift greenhouse. (My in-laws do just that to enjoy fresh tomatoes year-round in zone 4!)
There are a number of diseases that impact tomatoes and other members of the nightshade family, including eggplants, potatoes, and peppers. Many of these diseases can survive for months in the soil, and annual crop rotation is the best way to curb them. It can also be beneficial to plant tomatoes next to onion crops as a companion planting strategy, offering protection against various pests including aphids and Japanese beetle.
Growth Stages Of A Tomato Plant
Tomato plants are commonly categorized as either determinate or indeterminate. You might also see tomatoes divided up into bush and vining varieties. In most cases, the terms determinate/bush and indeterminate/vining are interchangeable.
Determinate (or bush) tomatoes grow to a certain size and then produce a large harvest all at once. A determinate tomato plant will flower and set fruit relatively early in the season compared to your average vining cultivar.
Because of their compact size, these varieties are highly recommended for container gardens. Determinate tomatoes also tend to have higher sugar content, making them ideal for sauces and other preserves.
Indeterminate (or vining) tomatoes require lots of space to climb and sprawl out. However, some modern cultivars have been bred to grow in small containers or hanging baskets.
In contrast to bush tomatoes, these plants produce flowers and set fruit throughout much of the growing season. On average, indeterminate tomatoes take longer to put out their first flowers when compared to bush varieties.
You’ll want to grow indeterminate tomatoes if your goal is to have a consistent, fresh crop throughout the summer. The majority of heirloom and cherry tomato cultivars are indeterminates.
Outside of these broad categories, nurseries and seed retailers often label tomato plants as early-, mid-, or late-season varieties. These labels may be applied to both determinate and indeterminate cultivars:
- Early-season tomatoes produce mature fruit about 55 to 70 days after transplant or 90 to 115 days after germination. Popular examples include ‘Early Girl’ and ‘Sungold’.
- Mid-season tomatoes produce fruit about 70 to 80 days after transplant or 110 to 125 days after germination. Popular examples include ‘Beefsteak’ and ‘Celebrity’.
- Late-season tomatoes produce fruit about 80 to 100 days after transplant or 125 to 145 days after germination. Popular examples include ‘Cherokee Purple’ and ‘Big Rainbow’.
Any time you’re researching season lengths of different tomato plants, I recommend paying attention to whether the days listed are counted from seed germination or seedling transplant. More often than not, it’s the latter and that can make a big difference in your garden’s harvest time!
1. Seed Germination
Tomato seeds typically measure 2 to 4 mm across and are light brown or tan in color. A single tomato fruit can contain 150 to 300 seeds.
Tomatoes must be sown indoors at least 42 to 56 days before the area’s last frost date. Even in zones 10 and 11, I find that gardeners usually start their tomato seeds in trays versus sowing them directly outdoors.
Tomato seeds take 6 to 8 days to germinate at temperatures between 65 and 85°F.
When tomato seedlings first emerge, they have two small leaves known as cotyledons. These cotyledons have been inside the seed the entire time and serve as a vital source of nutrition for the young plant as it germinates and sprouts!
All leaves that appear after the cotyledons will be mature foliage. It takes about 42 to 56 days for a tomato plant to transition out of the seedling stage and be ready for transplant to the garden.
3. Vegetative Growth
Your tomato plants need to be put on a considerable size to be able to support healthy fruit development in the near future. The bulk of the vegetative growth occurs 60 to 90 days after germination.
Determinate tomatoes grow to a specific size (determined by variety) before transitioning to flower production.
For indeterminate varieties, vegetative growth will more or less continuously throughout the entire growing season. However, plants will put on the most growth before flowering begins.
Proper nutrition is crucial to the vegetative stage of growth. Keep in mind, however, that applying excess nitrogen may encourage vigorous vegetative growth at the expense of good flower and fruit development.
About 60 to 90 days after germination, your tomato plants should begin flowering. Tomato flowers are not dissimilar to other nightshades such as tomatoes at this growth stage and are bright yellow and 1 to 2 cm across.
Individual flowers usually only last for a couple of days before wilting and eventually falling off of the plant. Tomato flowers will only develop into fruit following successful pollination.
Tomato flowers are self-fertile but pollen must be transferred to the pistil via pollinators, wind, or manual stimulation — e.g., a soft paintbrush.
You technically only need one tomato plant to produce fruit. With that said, pollination is much more likely when growing several plants in an area.
Cross-pollination is possible between different cultivars but won’t impact fruit development. It will, however, affect the genetics of any collected seeds.
6. Fruit Development and Ripening
Pollinated flowers will be replaced by small, immature fruit over the course of 14 to 21 days.
Tomatoes start out green and tend to stay this color until they reach their mature size. Most varieties turn bright red when 100% ripe. Since some cultivars bear yellow, purple, or even green mature fruit, though, it’s important to familiarize yourself with the type of tomatoes you’re growing.
Tomato Plant Growth Timeline – Timelapse Video
This short video is a beautiful illustration of a tomato plant going through each stage of growth from a seedling to a fruiting plant.
Note this plant was grown under artificial grow lights on a 24-hour light cycle during vegetation. This can significantly reduce the overall growth timeline compared to growing the plant under natural light.
When To Harvest Tomatoes
Depending on the cultivar, ripe fruit typically takes 25 to 60 days to develop after flowering (or 90 to 145 days after germination).
Tomatoes are somewhat unique in that they continue ripening for 7 to 14 days even off the vine. Many gardeners opt to harvest tomatoes when they are at their mature size but just before they turn red. This minimizes the chance of bruising or splitting while maximizing flavor.
The harvest season for determinate varieties is usually 4 to 6 weeks at most. Indeterminate tomatoes, however, can continue producing fruit for 8 to 12 weeks or more as weather permits.
FAQ Stages Of Tomato Plant Growth
- The University of New Hampshire Soil pH for tomato plants
Ben's horticultural interest grew when graduating from Hertfordshire University in 1997. Having contributed to numerous publications including Better Homes & Gardens, Garden Design Magazine, and The English Garden. He is also the author of Propagating Houseplants Made Easy.