Transplanting tomatoes into bigger pots
As a general rule, a plant should be replanted at the same depth it was growing initially. This holds true whether you’re transplanting zinnia seedling grown in a 6-pack, a shrub in a two gallon pot, or a tree that’s been ball-and-burlapped.
Tomato plants are different. They have the ability to generate roots along their stems, which is why it’s beneficial to plant them deeply. However, most plants do not produce roots from stem tissue. Burying a plant’s stem will usually cause rot or even the death of the plant. How to repot a tomato plant ?
How many times should you transplant tomatoes?
A strong tomato plant gets that way from a strong root system. Re-potting tomato seedlings gives roots room to grow.
Your tomatoes will have the best chance possible to develop a healthy root system when you re-pot them at least once (sometimes two or three times) before setting them in the garden.
What are the benefits of repotting tomato seedlings?
Repotting tomato seedlings might feel like unnecessary work if you just want to move things along, but there’s a good reason for it: This extra step allows you to take advantage of their remarkable talent to grow roots along their stems.
Tomato seedlings are unique in that they like their stems buried deeply. They have the ability to form new roots (called adventitious roots) along their stems, which help the plants grow more vigorously.
In fact, if you live in a humid climate, you may have even noticed adventitious roots forming above ground from tiny bumps (nubs) on the stem.
(I like to call them “air roots,” and contrary to what many people think, the fuzzy hairs on the stems do not turn into roots themselves — they contain the oils responsible for the distinctive smell of tomato leaves.)
Yes, every single one of those bumps has the potential to be a root!
Given ample moisture and sunlight, these roots will continue to grow like the ones underground and can even plant themselves in the soil if they get long enough.
Transplanting tomato seedlings deep in the soil stimulates the adventitious roots and creates a larger and healthier root system that will take up more nutrients and anchor your plant when it finally goes in the ground.
When should you repot tomato seedlings?
Deciding when to transplant tomato seedlings is easy. When tomato seedlings are three or four inches tall and have their second pair of leaves, it’s time to take them out of their crowded containers and put them into deeper, roomier ones. (If you started seedlings in individual containers at least three inches square, simply thin out the weaker plants by snipping them off at the soil line and leaving the strongest one.)
How to repot tomato seedlings
Seedlings will develop best if there is only one plant per pot. Instead of trying to untangle two seedlings that have germinated in the same pot, use a scissors to trim off the unwanted plant. Cut it off right at the soil surface, and you won’t disturb the remaining seedlings.
Use a small utensil, such as a table knife, to lift the transplants out of their original pots. Hold seedlings by their leaves — not their stems, as it is easy to crush the delicate stem tissues.
Make sure you choose a pot that’s wide enough and deep enough for the transplants. A 4-inch diameter pot that is 3-4 inches deep is usually adequate.
- You Will Need
- Tomato plants
- Multi-purpose, peat-free compost
Handle seedlings with care when easing them out of their containers for repotting to minimise root disturbance.
The tiny leaves below the first true leaves can be removed so that when the plant is potted deep into the compost, they’ll not rot.
Lower the plant into a larger pot so that the true leaves are just above the compost surface, filling in gaps and topping up the pot with multi-purpose compost. The stem below the surface will grow more roots, to boost the crop.
How to transplant tomatoes in pots (a second time)
Start with clean pots and fresh potting soil.
For the second round of transplanting, step up to 1-gallon pots. They don’t have to be disinfected first, but they should be clean and free of disease.
Have plenty of well-draining, well-amended potting soil on hand. I recommend mixing your potting soil with compost, or stirring in a granular tomato fertilizer before you plant
Pinch off the lowest sets of leaves.
With your fingers or a pair of garden scissors, pinch off the lowest two or three branches of leaves, especially if they’re wilting or yellowing. You will end up with a tall skinny stem with only a few branches on top.
Loosen the root ball and place the tomato plant in an empty pot.
Carefully loosen the root ball and place the transplant in an empty pot. The rim should be just below or even with the branches.
While it’s true that the roots are sensitive, they are not the most vital part of a tomato plant — the stem is. New branches, leaves, and roots continue to grow throughout its lifespan, but a tomato plant usually only has one main stem.
The plant cannot sustain damage to the stem, which should be treated with care during transplant. Handle the plant gently by its leaves or root ball, but avoid manhandling the stem.
Fill the pot with potting soil.
Fill the pot with potting soil, all the way up to its lowest branches. Give the pot a good final shake and add more soil as needed to stabilize the stem.
Resist tamping down on the soil with your hands or trowel (watering will do the work of settling everything in).
Water the tomato plant deeply.
Your newly transplanted tomato should have several inches of stem sunk below the surface. Water deeply down to the lowest roots and only water again when the first 2 inches of soil feels dry.
With a deep-rooted plant like tomatoes, the key is to water less frequently, but more thoroughly. Tomato plants like to be slightly dry in between watering and they will not tolerate being overwatered, so try to keep the moisture level consistent.
How big should a tomato plant be to transplant?
Generally, the right time to transplant is when your tomato plant reaches three times the height of its container. So if you’re moving from a 4-inch pot to the next size up, wait until your plant is 12 inches tall so there’s enough stem length to bury.
The progression of pots should go like this:
- Seed starting pots (or soil blocks)
- 4-inch pots
- 1-gallon pots
- Final container or garden planting
If you’re growing tomatoes in pots, the final container size should be 10 gallons (for determinate types) or 20 gallons (for indeterminate types).
If you’re growing tomatoes in the ground, plant them at least 18 to 24 inches apart (more space is always better for proper air circulation).
After transplanting to tomatoes in pots
After transplanting, pay extra attention to your plants for the first week or two. Apply a transplanting fertilizer if you like and make sure the soil doesn’t dry out. Keep the pots in a place protected from drying winds or excessive heat. Until the roots begin growing again, your transplants are very vulnerable to damage.
When your plants have grown two to three times the size of their pots, you can transplant them in the garden, again pinching off the lowest branches and sinking the stems deeper into the soil.