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Can Potatoes Grow Under Black Plastic

The conventional method of growing potatoes requires digging a trench, hilling dirt around the plants as they grow, and weeding. Then there’s the digging to harvest the potatoes you’ve grown. What if there was a way to grow them without those hours of labor while still providing them with the warm, dark environment they prefer? Can potatoes grow under black plastic?

Potatoes can grow under black plastic as well as mulch foils. You can plant your potatoes a little earlier because the black plastic will raise the soil temperature by 3-5 degrees. You’ll have less weeding, and harvesting your crop will be easier, too.

Now that you know that you can grow potatoes under black plastic, you may have more questions. Let’s dive into how to plant potatoes under black plastic, care for the plants as they grow, and the advantages and disadvantages of growing your potatoes with this method.

How Do You Grow Potatoes Under Black Plastic?

To grow potatoes under black plastic isn’t much different from planting them the usual way. But there is no need to dig trenches or hilling dirt around them as they grow. There is the added step of laying down the plastic. Follow these steps:

  1. Prepare the soil
  2. Lay the plastic over the bed
  3. Make holes for the potato plants to grow through the plastic
  4. Plant the seed potatoes in the holes
  5. Care for the plants while they grow

Prepare the Soil

After the danger from frost has passed, dig the bed where you’ll be planting the potatoes. Remove rocks and roots. Add compost and work it into the soil. Add fertilizer (for example, 10-10-10) and work into the top 6 inches of soil. If the soil isn’t damp, water it thoroughly. Smooth the surface with a rake so that it’s level.

Lay the Plastic Over the Bed

If you want to install a soaker hose under the plastic to make watering easier:

  1. Arrange it on the ground before putting down the black plastic.
  2. Roll the plastic over the bed and cut it to fit.
  3. Secure the plastic with brick or rocks or bury the edges in the soil so the wind will not tear it away.
  4. Don’t make it too tight.

Make Holes for the Potato Plants to Grow Through the Plastic

Cut 6″ Xs in the plastic one foot from the edge of the plastic and one foot apart. Tuck the edges of the X under to make a hole for planting.

Plant the Seed Potatoes in the Holes

Plant a seed potato 6″ deep in each hole and cover it with soil.

Water the entire area. Where puddles appear, poke a small hole in the plastic, so the water drains out. This will prevent water from accumulating in the low spots and let water under the plastic.

Care for the Plants While They Grow

Black plastic will reduce the need for watering by cutting down on soil evaporation. Monitor the dampness of the soil under the plastic. If you haven’t installed a soaker hose, you can water the entire area with a sprinkler or hose. The water will get into the soil at each plant’s hole, and through the holes, you poked in the low spots and along the edges of the plastic. Or you can water each plant individually.

You shouldn’t need to pull weeds unless a few grow out of the planting holes.

You can add fertilizer to each plant’s hole or use one designed for applying to the leaves of the potato plants.

If the soil gets too hot, you can apply mulch on top of the black plastic to help keep the soil cooler.

How Do You Harvest Potatoes Grown Under Black Plastic?

Planting potatoes this way rather than in hills means the potatoes won’t be deep underground. Harvesting the potatoes is just a matter of rolling back the plastic and picking out the potatoes. They will be growing near the soil’s surface.

You can collect new potatoes as they grow or wait for the plant to die and then dig them up. Let the soil on the potatoes dry, then brush it off. Let them cure for about two weeks in cool temperatures (45-60 degrees) to harden the skin. They’re then ready to store for later use.

What Are the Advantages of Black Plastic?

Heat

The black plastic will warm up the soil in the planting bed by 3-5 degrees. This means you can plant your potatoes earlier in the spring. The extra heat will give them a good start.

Weed Control

One of the best reasons to use black plastic is that it prevents weeds from growing. This will save you a lot of work in the garden. And the potato plants won’t be competing with weeds for water and nutrients.

Moisture

Covering your planting bed with black plastic will help keep moisture in the soil. Potatoes need a lot of water, so this will help reduce watering.

Harvest

The potatoes will grow under the plastic on the ground. There will be very little, if any, digging to get them. You roll back the plastic and pick them up off the ground.

What Are the Disadvantages?

Heat

The black plastic can cause the ground to get too hot for the potato plants and worms in warm areas of the country. One way to avoid damage is to add some straw or grass clippings on top of the plastic to help prevent the ground from getting too hot.

Slugs

Black plastic creates a warm, damp area to which slugs are attracted. You may need to use slug traps or other preventative measures.

Wind

Don’t try to lay it down on a windy day. If you live in a windy area, this may not be the best way to plant your potatoes. Be sure to cover or bury the edges of the plastic carefully, so it doesn’t blow away or get torn by the wind.

The Environment

A significant disadvantage of black plastic is that it’s not environmentally friendly. Most people will use plastic for one season. If you buy a thicker type, you may get two seasons from it, but you have to pull it up and store it.

Since it comes in rolls, it’s not that hard to lay it down, but picking it all up and then disposing of it is not that simple if you have a large garden you’re using it on.

Conclusion

You’ve seen how to use black plastic to cut down on the work required to grow potatoes – eliminating digging trenches, hilling up the dirt, and digging to harvest them.

You’ve also discovered the disadvantages of using black plastic. If you have hot summers or a lot of wind, then using black plastic may not be the best for your situation. You must weigh the pros and cons and the environmental aspect to decide if using this method to grow potatoes is right for you and your garden.