Growing potatoes in raised beds has many benefits. You’ll find they are easy to plant and care for, and yields are prolific. Potatoes thrive in the well-drained soil of a raised bed garden. Like tomatoes, peppers, and other vegetables, growing your own saves money at the supermarket, brings more flavor to the table, and if you harvest and store them correctly, you can enjoy your potatoes for many months to come. This article is a complete guide for successfully growing potatoes in raised beds.
In-ground growing vs raised bed growing
If you’ve grown potato plants in an in-ground garden, you know that they are not fussy plants. They do, however, require careful soil cultivation and a fairly long growing season. When growing potatoes in raised beds, the prep work is reduced, though the required growing season is still just as long. In-ground potato growing starts with tilling the soil, especially if it is compacted. But raised beds have minimal soil compaction, so tilling isn’t necessary. Also, raised bed potato growing also allows you to better control and target fertilization and watering, enabling your plants to receive the nutrition and irrigation they need to perform their best.
Plus, growing in a raised bed is easier on your back. You don’t have to bend over to dig through the soil to make the harvest. After many years of growing potatoes both in the ground and in raised beds, I can say without a doubt that potato-growing efforts in raised beds are far easier than growing in-ground.
The best raised bed depth for growing potatoes
To grow potatoes successfully in raised beds, there are a few matters to consider first. A proper raised bed depth should be your initial concern. Garden beds at least 10-12 inches deep are best for growing potatoes. Otherwise, there won’t be enough soil depth for a good crop to develop without the tubers being exposed to sunlight. Sunlight exposure turns potato tubers green. Green potatoes contain solanine, a compound that can make you sick if you eat them. Deeper beds are even better. My raised beds are 16-inches deep, which offers plenty of room for the tubers to develop beneath the soil.
Raised bed soil for growing potatoes
Next, think about the best soil to have in your potato-growing beds. It should consist of well-draining soil enriched with compost. The soil’s pH should be between 5.8 and 6.5, which is slightly acidic. This helps prevent a disease known as potato scab.
Incorporating organic fertilizers rich in phosphorus, such as bone meal, rock phosphate, or seabird guano can be helpful, especially if a soil test indicates your soil is deficient in phosphorus. Phosphorus is essential for good root and tuber formation, but care should be taken to not add more than necessary which can contribute to runoff pollution. You can read more about different fertilizer formulations and what they mean in this article.
When to plant potatoes
When growing potatoes in raised beds or in the ground, what you plant is called a seed potato. It’s really just a small potato or a chunk of a larger potato that was cut into pieces. As long as each seed potato contains at least one eye (growing point), it will grow into a new plant. Purchase certified disease-free seed potatoes from a reliable source to be sure you are not accidentally introducing a pathogen to your garden.
Plant seed potatoes in your raised beds in the spring anytime from two weeks before your last frost date to three weeks after your last frost date. For example, here in Pennsylvania, my last frost date is around May 15th. So, I can plant my potatoes anytime from April 30st through June 7th. If you live in a growing zone with a long frost-free growing season, you may even be able to plant them later than that.
Pay attention to the “days to maturity” noted in the seed catalog or nursery description of the variety you intend to grow. Make sure there are at least that many frost-free days in between your intended planting date and the date of your first expected fall frost.
How far apart to plant potatoes in raised beds
Use a shovel or trowel to plant your seed potato pieces about 10 to 12 inches apart, in offset rows spaced about 18 to 24 inches apart. The spacing is the same whether you’re growing in a raised bed or in the ground. Giving your potato crop room to grow is essential for good tuber production. Plus, having adequate air flow between plants can help prevent diseases like potato blight.
How deep to plant seed potatoes in raised beds
I like planting seed potatoes in a trench that runs down the length of my raised beds. A depth of about 5 to 6 inches is ideal.
You can also plant in very shallow trenches, but if you opt to do that, you’ll need to use a hoe to mound 3 to 5 inches of soil up around the shoots of the plants about a month after they begin to grow. This soil mounding buries more of the stem which increases the area from which potatoes can grow. It also keeps the developing tubers in the dark and prevents them from turning green.
I don’t like the process of mounding potatoes (too much work!), so I plant the tubers 6 inches deep and skip that step. However, if I notice a tuber developing too close to the soil surface, I will cover it with a few inches of soil or straw to keep it in the dark.
Caring for your potato plants
Once the sprouts of your potato plants begin to emerge from your raised bed, it’s time to shift into maintenance mode. Growing potatoes in raised beds isn’t difficult but following a few standard procedures can make your life easier.
If possible, once the stems are a few inches tall, mulch the bed with a layer of straw, EZ Straw, or shredded leaves. This cuts down on weeds and watering chores.
If you’ve incorporated plenty of compost into your raised bed prior to planting your seed potatoes, there’s no need to add a supplemental fertilizer later in the growing season. In fact, adding too much nitrogen can produce a lot of green top growth at the expense of good tuber yields.
How often to water potatoes growing in raised beds
Consistent moisture is an important key to supporting potato growth. Unfortunately, raised beds typically drain faster than in-ground gardens which may mean you’ll have to water more often. On the flip side of that, because raised beds are so well-draining there is little chance of them staying too wet and promoting tuber rot.
Potatoes need about 1 inch of water per week. To measure this, place a flat-sided and flat-bottomed container in the bed and turn on the sprinkler (I use an empty tuna fish can). When the container fills to an inch, then you know enough water has been added for the week. Take rainfall into account when determining this measurement, too.
Potatoes that are not consistently watered and go through long dry spells in between waterings may develop a physiological disorder known as “hollow heart” where they develop a hollow spot in the center. As mentioned earlier, mulch the bed with straw or shredded leaves to reduce watering needs and help prevent hollow heart.
When and how to harvest
There are two times you can harvest potatoes in raised beds. The first is after the plants have flowered but while they are still green and healthy. Tubers harvested at this stage are called new potatoes. Essentially, you’re digging out and enjoying some immature tubers before the plants have matured.
The main harvest, however, takes place about two weeks after the plants have turned at least 90% brown. At this time, the main crop of harvestable potatoes is dug from the soil. These are fully mature tubers that are better for long-term storage. Brush off the soil with your hand (do not wash them), then cure the potatoes to thicken their skins by laying them out on newspaper or cardboard in a cool dark spot (50-60°F) for two weeks. After they’re cured, store the potatoes in a cardboard box, bamboo storage bin, or bushel basket in a dark, cool room such as a basement or root cellar.
Raised beds for the win
Whether you’re growing ‘Yukon Gold’, fingerlings, or Russets, growing potatoes in raised beds results in great yields and less work for the gardener. Follow the guidelines found here and a hearty harvest is sure to follow.
For more advice on growing potatoes, please visit the following articles:
- How to plant seed potatoes
- When to harvest potatoes
- How to grow sweet potatoes
- How deep to plant potatoes
- Growing potatoes in small spaces
- What to plant after potatoes
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