How to Plant Potatoes in Raised Beds

About a month before the last frost date is the best planting time for potatoes in my zone 7b garden. That starts the planting season for potatoes here in Tennessee in Mid March. If you need a better guide than that think of St. Patrick’s Day and plan around it within a few days. Potatoes are not difficult plants to grow but there are a few things you can do to ensure a good harvest. Here’s some more information on planting potatoes in raised beds.

Planting Potatoes

When Planting potatoes in Raised Beds there are a few things you need. It’s a very short list!

• Seed potatoes (more on them in a minute)
• Soil Amendments
• A mulch of some kind

What are Seed Potatoes?

Seed potatoes are basically small potatoes. While potatoes will eventually flower and create seeds we aren’t really talking about actual seeds. The little bags of small potatoes you get for boiling or roasting in the grocery store work well for this. Seed potatoes can also be ordered online or bought locally at farmers coop stores.

For my planting this year I used some potatoes from a bag we bought at a grocery store. Some of the potatoes had already begun sprouting were ready for planting in the raised beds.

How to Make more Seed potatoes

You can also make seed potatoes from larger potatoes. Take your potatoes and let them sprout. Select potatoes that when cut will have at least 2 eyes. Those eyes are the buds that will grow roots and stems from energy stored in the potato. Cut the potatoes and let them sit for a few days then treat the cut ends with some type of fungicide. I generally will just use the small potatoes or whole large potatoes to reduce risk of diseases.

After you have harvested your potatoes at the end of the season save a few to cut and start your next season’s crop.

Before Planting Small Potatoes

Since my potatoes came from a grocery store they could carry diseases from the farm they were grown on. They were organic potatoes so I feel very comfortable with the potatoes themselves but you can never be too careful. To reduce my risk of potato diseases I soaked them for 30 minutes in soapy dishwater.

Prepping the Raised Beds for Potatoes

While the potatoes were soaking I prepped the raised bed. These are the same raised beds I used for tomatoes and peppers last year so let me offer a word of caution here: If you had a lot of trouble with diseases in a previous season don’t plant members of the same family in the same bed the following year. Fortunately I didn’t have any issues in my plants in this raised bed last year.

Tomatoes, peppers, and potatoes are all in the same family: Solanaceae, also known as the nightshades.

I made 4 trenches for the potatoes that were about 4-6 inches deep and spaced about 8 inches apart. They are extremely rich raised beds but I always add bone meal into the planting holes when planting. Bonemeal contains a high amount of potassium (K) which is used for root formation in plants. Here’s the bonemeal I typically use: Bonemeal (Aff. link)

After I prepped the beds I thoroughly rinsed the potatoes and began planting. I spaced them about 6 inches apart in the raised beds. After planting I ended with 24 plants planted in 4 rows. The potatoes fill up one half of the raised bed.

Potato Planting in Raised Beds Step By Step

• Dig trenches 4-6 inches deep.
• If in a rich planting bed space them 8 inches apart in rows 8 inches apart if you intend to take an earlier harvest of some of the potatoes. Otherwise increase the spacing to 12′ apart.
• Add bonemeal or other soil amendments to the trenches.
• Cover with soil
• Cover with mulch

Below is a video of planting our raised beds with potatoes.

Companion Planting the Potatoes

When things get warmer I may plant some basil as a companion plant for the potatoes. Companion plants are pairings of plants that complement one another either through efficient nutrient use or for pest repellent characteristics. Right now I could plant some greens like lettuce, spinach, or kale.

The key when selecting good companion plants is to avoid plants that utilize the same nutrients. Lettuce and other greens are grown for the leaves vs potatoes which are grown for roots. The greens will capitalize on nitrogen in the soil where the potatoes will soak up the potassium.

I like basil as a companion plant for tomatoes, peppers, and potatoes since it can shield the plants from insects that could be pests.

When to Harvest Potatoes

You can harvest small potatoes through out the season by gently digging the soil around the plants and removing the small potatoes. You can save some of those potatoes and replant for sequential crops. As a guideline watch for flowering and you should be able to harvest some new potatoes. They won’t be as sturdy as full grown potato tubers but you should still be nice and tasty!

Larger potatoes will need more time should be harvested after the plants turn yellow and the tops die back. Give them about a week or two after the die back for optimum timing.

Should You Hill Your Potatoes?

Hilling potatoes is done to prevent tubers close to the soil surface from getting light. When they get light they begin generating chemicals that are not good for consumption. Mulch more heavily or add soil when this happens. If you plant them deep enough in the raised garden bed to begin with you will avoid this issue.

Good Mulches for Potatoes

Probably the best type of mulch for potatoes is straw. It will retain moisture and break down over time. Also straw should not have weed seeds.

I’ve successfully used grass clippings that do not have weeds or seeds in them. I gather the grass clippings with a bagging more and spread them out over the soil areas of the potatoes. If you have invasive grasses that grow through rhizomes like Bermuda you may want to avoid using grass clippings. Also I highly recommend that you avoid using grass that was treated with chemicals.

Leaves are what I am currently using in the raised beds for a mulch. We gathered a bunch of leaves in the fall and covered the beds with them over the winter. The leaves will break down and feed the soil. There is a chance we picked up some weedy tree seeds but those should be easily pulled in the loose soil of the raised beds.

Are Potatoes Frost Tolerant?

Potato plants can handle a light frost OK. It isn’t ideal in any circumstance but a cloth sheet covering your potato plants may be all you need to protect them. Don’t use plastic unless you can tent it far enough over your plants where the plants do not touch the plastic. Plastic allows frost and cold to transfer right through it where cloth doesn’t.

A Couple Final Potato Growing Tips

• Keep the potatoes weed free. An adequate layer of mulch will help but if allowed to overtake your plants weeds will hurt your production.
• Watch for pests like potato bugs, flea beetles, aphids, or grubs. Take appropriate action. Diatemacheaous earth on the leaves may help with potato bugs and flea beetles. Insecticidal soap or a hard spray from the hose can take care of aphids. Grubs can even be dealt with by using a dish soap solution.
• Do plant companion plants nearby your potatoes to help deter some pests. Marigolds help prevent soil nematodes, catnip repels flea beetles, and basil may prevent potato beetles!
• Replenish your mulch as it breaks down.
• Watch closely for diseases. You can remove the lower leaves of the potato plant to help prevent water splashes from casting soil born diseases onto the plant.
• Bottom water to prevent fungal diseases.

What’s my Favorite Variety of Potato?

My favorite variety of potatoes are the gold potatoes. I love the buttery taste that the gold potatoes have. They are versatile as baked potatoes, french fries, and for all other cooking needs. Red potatoes are a close second!

All in all potatoes are an easy crop to produce. Most of the pests are easily dealt with and your potatoes will produce a bumper crop!