How Cold Is Too Cold For A Vegetable Garden?


It’s amazing to be able to grow vegetables in your own garden. But you need to be careful when to plant the vegetables. I wanted to know how much cold these plants can tolerate and have added my research below.

A temperature below 32 degrees Fahrenheit is too cold for a vegetable garden. This temperature will cause frost to develop in the garden that can damage the roots, leaves, and fruits in your vegetable garden. You can protect your vegetable garden if the temperature drop is temporary.

I’ve written a lot more details below of what temperatures the plants in your vegetable garden would survive. I’ve also written information about what you can do to protect your plants from a temporary drop in the temperatures.

What temperatures are too cold for vegetables?

I’ve added a list below of some of the vegetables and the temperatures that would be too cold for them to survive.

Vegetable Lowest temperature (Fahrenheit)
Tomatoes 32
Beans 31
Broccoli 29
Carrots 28
Cucumbers 30
Kale 27
Potatoes 28
Radishes 30
Spinach 30
Squash 30
Corn 32
Beets 29
Cabbage 26
Cauliflower 27
Okra 29
Pumpkin 31
Asparagus 30

How to protect your vegetables from surprise cold

You may find that some times the temperature drops below 40 degrees even when you’re in mid-May. There are precautions you can take in these surprise cold situations to protect your vegetable plants.

Use mulch

The best solution I recommend is to use mulch in your vegetable garden. Mulch is a layer of organic material that you lay 1-2 inches on the surface of the soil. This could be material like grass clippings, dried leaves, straw, or wood chips.

The mulch helps create a layer of insulation for the soil. This means that the temperature in the soil does not change drastically when the outside temperature fluctuates.

So when the temperature suddenly drops, it won’t affect the soil temperature in your vegetable garden. And gives your plant temporary protection from such low temperatures.

Use a heat sink

The next best solution I recommend is to create a heat sink that absorbs heat from the sun during the day and radiates it in your vegetable garden during the night.

This could be a simple thing like having a wall or fence in your garden near the plants. You could even grow trees that retain the heat they absorb during the day.

You can create a temporary heat sink by placing a dozen 1-gallon containers in your garden. These will absorb the heat from the sun during the day and keep it warm for the plants at night.

Use a row cover

The simplest temporary option you have is to use a row cover on your vegetable plants. Such a cover will keep your plants insulated from the temporary cold. This method works best for plants that have matured to a bigger size.

You can get specialized row cover material from your local garden center. Or you can use materials like landscape fabric, plastic, frost cloth, bed sheets, straw, or newspaper.

It’s important that the row cover does not touch the vegetable plants as that will conduct the cold to them. You can use bamboo stakes as support to create a tent with the row cover on top and the plants at the bottom.

I prefer using a material that allows some light, moisture, and air to reach the plants from the cover. You can keep such a row cover for a longer period of time without problems.

If you use a material like plastic or cloth, you need to take them off in the morning so the plants can get the required sunlight and air circulation. Otherwise, the plants risk stunted growth or infection by fungal diseases.

Use cloches

A cloche is a container that you can place on top of your plants to protect them from the temporary cold. This method works best for seedlings because they are small in size and can be covered with such a container.

You can use a water bottle container to build your own cloche. Cut the container in half and you can use both ends of the container.

Place the half of the container on top of the seedling to cover it from the cold. You can remove the lid from the container or make a hole at the top to allow air circulation if the weather gets warmer.

The cloche can act like a greenhouse trapping the heat inside. But when it gets warm, you don’t want your seedlings to get too hot. That’s why you’ll need to take them off when the weather gets warmer.

Move the containers

If you’re growing your vegetable garden in containers, it’s much easier to protect them from the temporary cold. You need to move the containers in a location that is warmer like your garage, basement, or patio.

Even if these places are not warmed up, they will still be warmer than the outside. This is because they absorb the heat during the day and radiate it during the night.

If you are unable to move your containers because they are too heavy, the other option is to wrap the plants with blankets until the weather gets warm again.

Make sure to wrap them loosely as you don’t want the blanket to touch the plants. You can attach the blanket to some stakes to keep them away from the plant.

When to plant vegetables

You can prevent your vegetable plants from suffering the effects of cold by choosing the right time to grow them. The vegetables can be either warm-season or cool-season plants.

Warm-season plants are those that prefer the warm climate of spring and summer to grow. cool-season plants are those that prefer the cold climate of early spring or late fall.

You should wait at least two weeks after the last frost date in your area to start growing the warm-season vegetables. Warm-season vegetables will grow well in temperatures between 50-85 degrees. If you have a short growing season in your area, you can consider starting the plants indoors and then moving them outside when the temperature is right.

You can grow the cool-season vegetables as soon as the last frost date in your area has passed. You can also grow them in fall when the temperature starts to drop. Cool-season vegetables grow well in temperatures between 40-75 degrees. Some of these cool-season vegetables taste better when hit by frost before harvesting.

What are some frost-tolerant vegetables?

If you grow some of these frost-tolerant vegetables, you will not have to worry about a drop in the temperature because they plants have no issues with it.

  • Lettuce
  • Carrots
  • Spinach
  • Turnips
  • Collard
  • Swiss chard
  • Parsnips
  • Broccoli
  • Kale
  • Leeks
  • Brussels sprouts

How can I tell if my seeds were damaged by cold?

If you have planted seeds in your vegetable garden and it was hit by a temporary drop in temperature, you need to check the condition of your seeds.

If you find that the seeds have not germinated even after a couple of weeks, you can dig into the soil and check their condition. If the seeds have turned black and soggy, they’re dead and you will need to re-plant new ones.

If the seeds are healthy, I would suggest to wait for a couple of weeks and allow the seeds to germinate. Some of the seeds may go dormant due to the drop in temperature but they will bounce back as the temperature returns to normal.

If you find that the seeds are not germinating even after a couple of weeks, you can move them indoors in a seed-starting tray. They have a better chance of germinating in a warm and comfortable environment indoors.

Kevin

Kevin’s sick of eating mass-produced vegetables that contain harmful chemicals and lack nutrition and taste. He wants to grow his own food and help others do the same even with limited growing space.

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