Why Are My Tomato Plants Falling Over? (3 Ways to Stop It)


Are you worried about some of your tomato plants that are bending or falling over?  If so, you’re not alone.  It is normal to see this problem in your garden and wonder what is going on.

So, why are your tomato plants falling over?  Tomato seedlings may look like they are falling over due to damping off (fungus) or a lack of light.  Young tomato plants may fall over after transplant due to transplant shock or lack of hardening off. Mature tomato plants may fall over due to a lack of support.

Of course, it would be nice to know which of these things is making your tomato plants fall over. That way, you can treat the problem and get back to growing nice, healthy plants.

In this article, we’ll take a closer look at the things that make tomato plants fall over. We’ll also discuss how to tell which one is making your tomato plants fall over and how to solve the problem.

Let’s get started.

Why Are My Tomato Plants Falling Over?

There are several possible reasons that your tomato plants are falling over. The cause depends on the age of the plant and the environment it is in:

  • For seedlings (tiny baby tomato plants that germinated recently) – the most likely causes of falling over are damping off or lack of light.
  • For young tomato plants (small tomato plants that are ready for transplant into the garden) – the most likely causes of falling over are transplant shock or a lack of hardening off.
  • For mature tomato plants (tall tomato plants several feet tall that may already have flowers or fruit) – the most likely cause of falling over is lack of support.
tomato seedling
Tomato seedlings will start to get tall and fall over if there is a lack of light.

Let’s start with an explanation of damping off, when it happens, and what causes it.

Damping Off Of Tomato Seedlings

According to Wikipedia, damping off is a plant disease that weakens or kills seedlings.  Damping off is caused by fungus, and is more common in wet and cool soil.

Look for the following signs to tell if your tomato seedlings have damping off:

  • Thin, tough, wiry stem
  • Spotted leaves
  • Grey mold on stems or leaves
  • Rotten roots
damping off seedling
Any seedling that suffers from damping off (caused by fungus) will not look so good.
Image courtesy of user:
INAKAvillage211 via:
Wikimedia Commons:
https://commons.wikimedia.org/wiki/File:
Pinus_taeda_seedling_
damping_off_(cropped).jpg

How To Prevent Damping Off Of Tomato Seedlings

To prevent damping off, take the following steps:

  • Use sterile soil – don’t reuse garden soil or potting mix. Old soil may have soil-borne diseases from previous years.  Instead, buy clean and fresh potting mix to start your tomato seeds.
  • Keep soil warm and moist – damping off is more likely to happen in cold soil.  Cold or dry soil also delays seedling germination and slows the growth of seedlings.  The faster tomato plants grow, the sooner they get strong enough to resist damping off. Your best bet to avoid damping off is to keep the soil warm and moist to encourage fast germination.  You can learn more about the ideal conditions to germinate tomato seeds in my article here.
  • Quarantine plants – if any seedling starts to look sick, pull it out to separate it from the other seedlings.  This will help to prevent the spread of any disease between plants. (If you are worried about not having enough plants, start a new tray or pot of seeds to make some more seedlings).
tomato seedling
If any seedlings show signs of damping off, remove them to avoid infecting other plants.

Lack Of Light For Tomato Seedlings

Maybe your seedlings don’t show any signs of damping off.  In that case, a lack of light may be the reason they are falling over.

According to the University of New Hampshire, tomato plants require full sunlight, growing best in areas that receive full sun for most of the day.

After tomato seeds germinate and seedlings emerge from the soil, they need light to continue growing.  Seedlings will do what is necessary to get enough light.

If light is stronger in one direction, a seedling will lean over and grow towards the light.  This can give it a bent over appearance, making it look like the seedling is falling over.

Without enough sunlight, seedlings will get tall and may bend over.

If the light source is far above the seedling, it will grow tall and thin to reach up and get closer to the light.

If you keep your seedlings in an area where they don’t get enough sunlight, they will start to get leggy (tall, thin, and spindly).  Even if you put them under a grow light, they will grow leggy if the light is too far above them.

You can learn more in my article on why your tomatoes growing so tall.

To avoid tall and leggy tomato plants that may bend over or fall over, give them consistent light.  Put them in a window sill on a south-facing side of your house.

If that isn’t possible (or if it doesn’t give enough sunlight), use grow lights instead (LED or fluorescent bulbs are good choices, while incandescent bulbs waste a lot of energy by producing a lot of heat).

Make sure to put the tomato plants close enough to the grow light (their tops should be a few inches away, depending on how powerful the lights are).

LED lights
An LED is a good option for a grow light, since it doesn’t waste a lot of energy on heat production.

To learn more, check out this article from Grow Light Info on how close to put grow lights to plants.

Transplant Shock Of Tomato Plants

If your tomato plants are just past the transplant stage, then they may be suffering from transplant shock.  If the shock is severe enough, some of your plants may fall over.

Transplant shock can happen for several reasons:

  • Root Damage – this often happens during transplant if seedlings grew close together and got their roots tangled up together.  It can also happen if you leave transplants out in the sun with their roots exposed while they wait to be planted. To avoid this problem, handle transplants gently and remove them from their trays or pots right before they go into the soil.
  • Lack of Hardening Off – if you didn’t harden off your plants, then they might be in for a shock when they go outside.  The change in temperature, moisture, and wind can be too much for them to handle all at once.
tomato plant roots
Tomato plant roots can be damaged during transplant, which might cause a plant to fall over later due to transplant shock.

How To Prevent Transplant Shock

To prevent transplant shock, all it takes is a little care when transplanting your tomatoes to the great outdoors.

First, when planting seeds, leave them enough space so that their roots don’t get tangled in the first place.  Another option is to use a seed tray with individual cells (one for each seedling).

seed tray
Use a seed tray with individual cells to prevent seedlings with tangled roots.

Leaving enough space between seeds will prevent seedling roots from getting damaged during transplant.  It will also reduce the chances of disease spreading between plants.

Also, harden off your plants by introducing them to the outdoors gradually.  Start off by giving them more exposure to sunlight, wind, and outdoor conditions over time.

A greenhouse or cold frame is one way to give plants an easier transition to the outdoors.  For more ideas, check out my article on hardening off seedlings.

Finally, when you transplant your tomato plants into the ground, keep their roots out of the sun.  Keep them safe in their containers until right before you plant them.

Lack Of Support For Tomato Plants

If your mature tomato plants are falling over long after transplant, then it is probably due to a lack of support.  As tomato plants grow taller, they get heavy as they produce more vines, leaves, and fruit.

heirloom tomato
As tomato plants produce more branches and fruit, they are more likely to fall over due to the weight.

Eventually, this extra weight wants to fall in one direction.  Without support, the tomato plant will bend over and start to crawl along the ground (in fact, this is the plant’s natural inclination!)

This can give soil-borne diseases more of a chance to infect your plants.  To avoid this, you will need to support your tomato plants (and possibly prune them).

How To Keep Tomatoes From Falling Over

To keep your tomato plants from falling over, you will need to provide some kind of support.  Depending on the variety, it might also make sense to prune them, so let’s start there.

Prune Tomato Vines

As tomato plants grow, they will produce more suckers (young branches).  These suckers will later grow into large branches with leaves.

These branches may also produce flowers and fruit.  Either way, they add extra weight to the plant.

They can also make it more difficult to manage the plant, to harvest the fruit, and to support the vines.  You can prune your tomato plants to avoid this problem.

Generally, you should only prune indeterminate tomato varieties.  Leave determinate tomato varieties alone.

pruning shears
You may want to prune indeterminate tomato varieties, but leave determinate varieties alone.

You can tell which type of tomato plants you have by checking the seed catalog or packet.  You can learn more about how to prune tomato suckers in my article here.

Support Tomatoes

Your tomato plants will need support when they get taller, whether you prune them or not.  You can use stakes, cages, or trellises for this purpose.

There are lots of ways to support tomato plants.  The method you use will depend on the type you are growing (how tall they get and their growth habit).

Stakes For Supporting Tomatoes

Stakes are one good way to support tomato plants.  They are often used to support taller indeterminate tomato varieties, which tend to grow very long like vines.

However, you can use shorter stakes as support for indeterminate varieties as well.  You can find tomato stakes made of wood (including bamboo), metal, or plastic.

tomato stakes
Tomato stakes are good for supporting taller indeterminate tomato varieties.

It is a good idea to drive the stakes deep into the ground (at least a foot) before transplanting your tomatoes.  Put the stakes right next to the spot where the plant will go.

If you put up stakes later in the season after planting, you risk harming the roots of an established plant.

If you already planted your tomatoes and have no stakes, don’t worry.  You can use a tripod or teepee to give your plants support.

Drive 3 or 4 stakes into the ground around the plant.  The stakes should be at an angle, and they should come together above the plant.

Tie the stakes together with rope or twine to keep them steady.

According to the Penn State University Extension, you can also use the “Florida Weave” method of supporting your tomatoes with stakes.  Drive stakes into the ground in a row, right next to the row of tomatoes.

Then, run a length of rope, twine, or wire between the stakes at varying heights (every 6 to 12 inches of height).

You can learn more about the various methods of supporting tomato plants in my article here.

Cages For Supporting Tomatoes

Cages are another way to support tomato plants.  Cages are often shorter than stakes, and they surround the whole tomato plant.

A cage will support a tomato plant no matter which way it decides to lean.  Tomato cages are more often used to support determinate tomato varieties, since they are shorter and tend to grow wide like bushes.

plant cage
A tomato cage surround a plant, so it will provide support no matter which way the plant grows.

You can buy (or make) tomato cages out of metal, plastic, or wood.  If you build a custom tomato cage, you can make it as tall or wide as you want.

You can learn more about tomato cages in my article here.

Trellises For Supporting Tomatoes

A trellis is another option for supporting tomato plants.  In addition to supporting plants, a trellis can give a nice look to your yard, garden, or patio.

wood trellis
A trellis is one way to support tomato plants while giving your yard a nice appearance.

You can put a trellis on the side of your house, lean it up on a fence, or put it against one wall of a pergola.  If you use a wide trellis, you might be able to support several tomato plants at once.

If you want to build your own trellis, I have an article to help you get started with the best materials and where to find them.

Conclusion

Now you have a better idea of why your tomato plants are falling over.  You also know some steps you can take to fix the problem or prevent it in the future.

If any of your tomato plants have broken stems, you can learn how to save them in my article here.

You might also be interested in learning about what you can use for tomato ties.

I hope you found this article helpful.  If so, please share it with someone who can use the information.

If you want to read some of my most popular posts, check out the “Best of GreenUpSide” page here.  Enjoy!

~Jonathon

jonathon.david.madore

Hi, I'm Jon. Let's solve your gardening problems, spend more time growing, and get the best harvest every year!

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