Tomato Growth Stages: Is My Plant On Track?

The timeline, from transplant

A slicing tomato runs about 73 days from transplant to first ripe fruit. Cherry types come in sooner, often around 60, and paste types run longer. Count from the day the plant went in the ground, not from when you sowed the seed, because that is what the days-to-maturity figure on a transplanted tomato means.

Rough shape of those weeks:

• Week 1: no visible growth. The plant is making roots and this stage looks like nothing is happening.
• Weeks 2 to 3: new leaves appear at the top and the stem thickens. This is when growth becomes obvious.
• Weeks 4 to 5: first flower clusters open. On an indeterminate plant, flowering and growing continue together from here.
• Weeks 5 to 7: first fruit sets and sizes up while staying hard and green.
• Weeks 8 to 9: first fruit reaches full size, still green. It will sit like this for a while, which alarms people.
• Weeks 10 to 11: color break, then ripening. About 73 days in for a slicer.
• Weeks 11 onward: picking continues for roughly 6 to 8 weeks, totaling about 12 lb from one slicing plant.

The stall that is not a stall

The most common worry is a full-size green tomato that sits unchanged for two or three weeks. That is normal, and it catches almost every first-year gardener.

A tomato grows to its final size while green and only then begins to ripen, and the ripening phase is slow and driven by temperature. The plant is not stuck. It is doing the part that has no visible progress.

Heat actually pauses it. Ripening slows above roughly 85F and the red pigments are poorly produced in high heat, which is why tomatoes in a hot spell go from green to a pale orange and stop. A run of cooler days finishes them.

The related thing worth knowing: once a tomato reaches color break, that faint blush at the blossom end, it has cut itself off from the plant and will finish ripening on a counter just as well as on the vine. That is your escape hatch when frost is coming or when something keeps eating them.

Flowers but no fruit

The stage that genuinely does fail is flower to fruit, and it is nearly always temperature rather than anything you did.

Tomato pollen becomes unviable in heat. Nights above roughly 75F and days above about 90F cause flowers to open, fail to pollinate, and drop off at the stem. You get a plant that flowers heavily through a hot stretch and sets nothing. It resumes on its own when the weather breaks.

The other version is cold. Below about 55F at night the same thing happens for the opposite reason, which is why tomatoes set out too early flower and drop.

What it is usually not: fertilizer. Heavy nitrogen produces a large leafy plant with few fruit, so if your plant is enormous, dark green, and barely fruiting, the problem is too much feeding rather than too little. Cut the nitrogen and it will shift back to fruit.

Determinate and indeterminate run on different clocks

Which type you have changes what a normal timeline looks like, and mixing them up is why one gardener's chart does not match another's plant.

A determinate tomato grows to a set size, around 24 to 30 inches, sets all its fruit in a short window, ripens most of it within a couple of weeks, and then declines. If yours stops growing and dumps its whole crop at once, that is not a failure, that is the variety. These are the canning tomatoes, because you want the harvest concentrated.

An indeterminate tomato keeps growing and keeps setting new flowers until frost, reaching 3 to 5 feet and often more. Fruit and flowers appear on the same plant all season. If yours is still throwing new growth in September, that is correct behavior.

So the check is: read the packet before you judge the plant. A determinate that quit in August is finished on schedule. An indeterminate that quit in August has a problem.

When a stage really is going wrong

A short list of what is worth acting on, since most of what looks alarming is not.

Leaves curling upward in heat is usually just water stress and self-corrects in the evening. Leaves yellowing from the bottom up, with brown spots that have rings in them, is early blight and it spreads.

A sunken dark patch on the blossom end of otherwise good fruit is blossom end rot. It is a calcium delivery problem driven by uneven watering rather than a calcium shortage in the soil, so the fix is consistent moisture and mulch, not a calcium product.

Fruit splitting in rings or lines after rain is the plant taking up water faster than the skin can stretch. Steady watering prevents it, and split fruit is still fine to eat right away.

The one test that settles most of it: if new growth at the top of the plant looks healthy, the plant is fine and you are looking at old damage. If the new growth is wrong, act.