When to harvest potatoes

Sarah_Taufiq · May 26, 2021, 7:25pm

When to harvest potatoes? Potatoes are ready to harvest when the foliage begins to die back. The tops of the plants need to have completely died before you begin harvesting. Temperatures of both the air and soil should also factor into when to dig. Potatoes are tubers and you want your plant to store as much of that flavorful starch as possible.

There are two main types of potatoes: new potatoes and storage potatoes, and both harvesting time and techniques differ between the two types. Figuring out when to harvest potatoes can be a challenge for new gardeners, but once you know the basics, timing the harvest is a snap!

New Potatoes – All potatoes can be new potatoes if harvested when the tubers are still small and thin-skinned, about 50 to 55 days from planting for early maturing varieties. The first sign that new potatoes have formed is the appearance of the flowers. At that point, feel free to start harvesting.
Storage Potatoes– Storage potatoes, also called main-crop potatoes, are ready at the end of the growing season when the foliage has turned yellow and begun to dry. Some gardeners cut off the foliage while others allow it to die back naturally. Either way, the tubers need to be left in the ground for about two more weeks. This allows the skins to thicken up, which results in better storage quality.
Potatoes can tolerate light frost, but when the first hard frost is expected, it’s time to get out the shovels. In areas where the fall is cool, but without frost, soil temperature will dictate when to pick potatoes. Your soil needs to be above 45 F. (7 C.)

Here are 10 steps to grow potatoes in small spaces:

Step 1: Pick the right variety
Start your tater-growing adventure by deciding what variety of potato to grow. Russets are great for baking and storing, fingerlings are perfect pint-sized spuds, and heirloom varieties come in a rainbow of colors and textures (the potato in the feature image is an heirloom called ‘All Blue‘). No matter what type you choose, be sure to purchase certified disease-free seed potatoes from a reliable source.

Step 2: Make the cut
Officially speaking, seed potatoes aren’t seeds at all. They’re fully developed potatoes that are cut into pieces and planted like a seed. Use a clean, sharp knife to cut each tuber into several sections, being sure each section contains at least one “eye” and an inch of flesh. Let the cut potatoes rest for 24-48 hours before planting. This rest period enables the cut area to callous over and helps keep soil-borne diseases from rotting the tuber before it can grow.

Step 3: Find a place
Thankfully, potatoes aren’t overly particular about where they grow, but they do produce best where they receive a minimum of six to eight hours of direct sun. Select your planting site accordingly.

Step 4: Set up the bin
Growing potatoes in a bin may just be one of the most fun things you’ll ever do in the garden. It’s easy, and the plants are surprisingly productive. Make a three- to four-foot-wide cylinder of box wire or chicken wire fencing. I like to use fencing that’s four feet tall. Line the inside of the wire bin with a layer of newspaper about ten sheets thick. Fill the bottom eight inches of the bin with a 50/50 blend of compost and potting soil.

Step 5: Plant the taters
Put the cut seed potato sections on top of the compost/potting soil blend. How many seed potatoes you add will depend on the bin’s diameter. When I grow potatoes in small spaces using this technique, I usually put eight to ten pieces per bin. Then, I cover the seed potatoes with another three inches of the potting soil/compost mix. Over the coming weeks, as the plants grow, fill the rest of the container little-by-little with the compost mix until it reaches the top. This technique serves the same function as “hilling” does – it allows more stem area below ground for potato production.
The only negative when you grow potatoes in small spaces like this is the constant need to water. Potatoes need to be consistently moist, so a daily dousing during summer’s heat is an absolute must. If Colorado potato beetles become problematic, cover the plants with floating row cover.

Step 7: Digging your potatoes
The potatoes are ready to harvest after the plants turn completely brown and die. Allow the tubers to sit in the ground two to three weeks beyond the death of the plants. This resting period is necessary to harden off the skins and make them better able to withstand long periods of storage. To harvest, simply open the wire cylinder and dig through the soil with your hands to uncover the spuds.

WHEN TO PLANT POTATOES

PLACE	MONTH	SEASON
Northern Region	Mid-April	Spring
Southern Region	September to February	Winters

Potatoes prefer cool weather.
In Northern regions, some gardeners will plant the first crop of early-maturing potatoes in early to mid-April, 6 to 8 weeks before the average last frost date or as soon as the soil can be worked; they can survive some cool weather but the threat of frost is a gamble. If there is a threat of frost at night, temporarily cover any sprouted foliage with mulch or an artificial covering such as old sheets or plastic containers (and be sure to remember to remove the coverings in the morning).

To avoid frost, consider starting potatoes 0 to 2 weeks after your last spring frost. You may plant earlier, as soon as soil can be worked, but be aware that some crops may be ruined by a frost or overly wet soil.

The soil, not the calendar, will tell you when it’s time to plant. The temperature of the soil should—ideally—be at least 50°F (10°C). The soil should also not be so wet that it sticks together and is hard to work. Let it dry out a bit first. Like other seeds, potato seed pieces will rot if planted in ground that’s too wet.

In Southern regions, potatoes can be grown as a winter crop and planting times range from September to February. Where winters are relatively mild, you can plant a fall crop in September. In central Florida, gardeners plant potatoes in January; and in Georgia they plant in February.

PREPARING THE PLANTING SITE

• Potatoes grow best in cool, well-drained, loose soil that is about 45° to 55°F (7° to 13°C).
• Choose a location that gets full sun—at least 6 hours of sunlight each day.
• Grow potatoes in rows spaced about 3 feet apart.
• With a ■■■ or round-point shovel, dig a trench about 6 inches wide and 8 inches deep, tapering the bottom to about 3 inches wide.
• Spread and mix in fully-rotted manure or organic compost in the bottom of the trench before planting

HOW TO GROW POTATOES

Hilling Potatoes
A critical part of growing potatoes is to not let their tubers (i.e., the potato crop) be exposed to sunlight for too long. Exposed tubers will turn green and produce a toxic compound called solanine, which makes them bitter, inedible, and potentially nausea-inducing.

To combat this, we employ a technique called hilling.

Hilling is simple: As a potato plant grows, it produces a main stem with leaves and flowers aboveground. Meanwhile, underground, tubers form on secondary stems that branch off from the main stem. In order to prevent shallow tubers from being exposed to sunlight and to encourage the plant to keep producing more tubers, a few inches of soil are periodically “hilled” up around the base of the stem. This is typically done three to four times during the season.

Tips for growing and hilling potatoes:
Do the hilling in the morning, when plants are at their tallest. During the heat of the day, plants start drooping.

Maintain even moisture, especially from the time when sprouts appear until several weeks after they blossom. The plants need 1 to 2 inches of water per week. If you water too much right after planting and not enough as the potatoes begin to form, the tubers can become misshapen.

The last hilling should be done before the potato plants bloom, when the aboveground part of the plant is at least a foot tall. ■■■ the dirt up around the base of the plant in order to cover the tubers as well as to support the plant.

PESTS/DISEASES

Potato Scab: Most likely caused by a high soil pH. Remember: Potatoes like acidic soil (do not plant in soil with a pH higher than 5.2). Dust seed potatoes with sulfur before planting. Some readers suggest adding pine straw on top of the potatoes when planting for natural anti-bacterial elements.
Colorado potato beetles need to be hand-picked and predatory birds will often eat them. While they’re in the ■■■■■ state, they can be controlled with diatomaceous earth (food grade) which is a non-toxic way to control pests in the garden. If they continue to be a problem, a few sprays of Spinosad, an organic pesticide, will get rid of the beetles. Always use products at dawn or dusk to avoid harming beneficial insects.

• Preventing Potato Blight
The dreaded fungal disease known as the "potato blight” (Phytophthora infestans) was responsible for the Irish potato famine and can destroy your entire crop, too. To reduce the chance of infection, never plant potatoes (or tomatoes and other members of the nightshade family, such as eggplants or chili peppers) in the same patch of land without leaving an interval of at least three years. Also, promptly remove any volunteer potatoes that emerge in your garden. The disease overwinters in tubers left behind during the previous year’s harvest.
• Aphids
• Flea Beetles
• Early/Late Blight
• HARVEST/STORAGE

WHEN TO HARVEST POTATOES

PLACE	MONTH	SEASON
Southern region	April	Spring
Northern region	September to January	Winter

Regular potatoes are ready to harvest when the foliage begins to die back. (See each variety for days to maturity.) The tops of the plants need to have completely died before you begin harvesting.

“New potatoes,” which are potatoes that are purposefully harvested early for their smaller size and tender skin, will be ready for harvest 2 to 3 weeks after the plants stop flowering. New potatoes should not be cured and should be eaten within a few days of harvest, as they will not keep for much longer than that.
Toughen up potatoes for storage before harvest by not watering them much after mid-August.

Dig up a test hill to see how mature the potatoes are. The skins of mature potatoes are thick and firmly attached to the flesh. If the skins are thin and rub off easily, your potatoes are still too new and should be left in the ground for a few more days.
Potatoes can tolerate light frost, but when the first hard frost is expected, it’s time to get out the shovels and start digging potatoes.

HOW TO HARVEST POTATOES

Cut the brown foliage off and leave the potatoes for 10 to 14 more days before you harvest. This allows the potatoes to develop a thick enough skin. Don’t wait too long, though, or the potatoes may rot (especially in moisture-laden soil).
Dig potatoes up on a dry day. Dig up gently, being careful not to damage the tubers. Avoid cutting or bruising potato skin. Damaged potatoes will rot during storage and should be used as soon as possible. The soil should not be compact, so digging should be easy.
If the soil is very wet, let the potatoes air-dry as much as possible before putting them in bags or baskets.
Don’t leave the potatoes that you have dug in the sun for long after they have been dug up from your garden, otherwise your potatoes may turn green. Green potatoes have a bitter taste due to the presence of solanine, and if enough is eaten, can cause vomiting and diarrhea. Small spots can be trimmed off, but if there is significant greening, throw the potato out.

CURING POTATOES
Allow freshly dug potatoes to sit in a dry, cool, dark place (45 to 60°F / 7 to 15°C) for up to two weeks. This allows their skins to cure, which will help them keep for longer.
After curing, make sure you brush off any soil clinging to the potatoes.
Whether you dig your own potatoes or buy them at a store, don’t wash them until right before you use them. Washing potatoes shortens their storage life.
After curing, do not put potatoes near apples; the apples’ ethylene gas will cause potatoes to spoil and go bad.

How to store potatoes

Before they can be stored, potatoes need to go through a curing process. This helps the skin thicken up and extends the storage life of the tubers. To cure potatoes, lay them on newspaper, trays, or cardboard in a cool, dark spot (50 to 60 F, 10 to 15 C) with high humidity for one to two weeks. Pick a location that offers good air circulation.

Once cured, move the potatoes (removing any that have signs of damage) to bushel baskets, cardboard boxes (with ventilation holes poked in the sides), low baskets, or brown paper bags. You can also find multiple drawer harvest storage at many garden supply stores. Don’t pile them too deeply, however as that can encourage rot to spread. Cover containers with cardboard or sheets of newspaper to block light.
The storage area should be cooler than the curing site and be dark and well-ventilated. I use a corner of my basement, but a root cellar is best if you have one. Aim for a temperature of 40 to 45 F (4.5 to 7 C) with high humidity. Under ideal conditions, storage potatoes can retain quality for six to eight months. Check tubers regularly and remove any that show signs of rot or shriveling.

The thin skin that makes new potatoes so appealing limits their storage life to weeks not months. Therefore, enjoy new potatoes soon after harvesting them.

More potato growing tips:

• If you don’t want to bother with hilling, plant your potatoes 8-9 inches deep. The downsides are: the potatoes take longer to sprout and your harvest might be smaller.
• Potatoes like slightly acidic soil (5.8-6.5 pH). Add fertilizer or composted manure for best results.
• When growing potatoes in containers, a good soil recipe is 1 part peat moss, 1 part organic potting soil and 1 part cow manure.
• If you want to make the task of weeding easier (and you have the space), plant your potatoes at least two feet apart so that you can weed around them easily.

Frequently Asked Questions

1- How do you know when it’s time to dig up potatoes?

It’s time to dig up your tender, homegrown potatoes when the buds drop or the flowers that do bloom begin to fade. Another good indication is seeing unopened flower buds dropping from the plant. At this point, the leaves will still be green but some will begin fading to yellow.

2- Can you harvest potatoes too early?

The plant could look large and healthy, but the potatoes themselves may only be small and immature. If you harvest your potatoes too early, you can miss out on a heavy crop, but if you wait too long, they could be damaged by frost. To pick the best time for digging potatoes, watch what’s happening with the foliage.

3- How long can you leave potatoes in the ground?

When storage temperatures exceed 45 degrees, potatoes should keep for two to three months, but sprouting and shriveling may occur. “Planting sprouted, shriveled tubers the following spring is not recommended because of excess disease levels, particularly viruses,” Mosley said.

4- How many potatoes will one plant produce?

You can expect about three to six regular-sized potatoes and a few smaller ones from each plant.

5- What happens if you don’t harvest potatoes?

If you don’t harvest potatoes when the plant dies back, a couple of things could happen. Most likely they will rot if the soil is wet, or they’ll die once the ground freezes. But if you live in a warm and dry enough climate, any tubers that survive over the winter will sprout again in the spring.

6- Can you eat potatoes right after harvest?

About 99% of all the potatoes you’ll ever eat have been grown to maturity, dug from the ground, and then “cured” – stored for a period of 10 days to 2 weeks in a climate-controlled environment. … Truly new potatoes are sold right after harvest, without any curing.

7- Can you dig potatoes before they have flowered?

When the flowers appear on the shoots and stems of potato plants, it’s a sign that the potato tubers are maturing. With main crop potatoes, wait until the stems have died down completely before lifting. As a guide, harvest first and second earlies 10-12 weeks after planting.

8- Can you replant potato plants after harvest?

Well, the potato is quite sensitive to being moved and it’s really important to give the roots an opportunity to grow properly in its new spot. So to sum it up, you can basically transplant potato plants to any given spot in your garden.

9- How many potatoes should you plant and how deep?

Potatoes are easy to grow – one seed potato will produce many potatoes to harvest. Prepare the soil by digging and removing weeds, and then dig straight trenches 12cm deep and 60cm apart. In spring, plant seed potatoes 30cm apart and cover them with soil to fill the trench.

10- How often should you water potatoes?

Potatoes grow best when they have a steady supply of 2-3 inches of water per week without fully drying out. Potato plants should be watered deeply, especially if it gets very hot and dry. The soil should be moist 8 to 10 inches underground. Make sure not to overwater the potatoes for 2 weeks after planting.

11- How do you increase the yield of a potato?

The two key yield components of potato are tuber numbers per unit area, and tuber size or weight. Increased yields come from achieving the optimum tuber numbers, maintaining a green leaf canopy, and increasing tuber size and weight.

12- When should I stop watering my potato plants?

Potatoes use 1 to 2 inches of water per week. Water the potatoes as evenly as possible. This helps the tubers to have a uniform shape and helps make a better yield. Stop watering about 2 weeks before harvest or when the vines turn yellow and naturally die after 90 to 120 days.

13- Can I cut the tops off my potato plants?

To trim your edible potato plants, pinch off the blossoms as soon as they appear on the plant, or snip them off with shears. … Prune the plant down to ground level, 1 inch (2.54 cm.) above the soil surface. Don’t cut them any lower than this, as you may expose the tips of shallow potatoes.

14- Why are my homegrown potatoes so small?

Small potatoes can be caused by a lack of sunlight, improper watering, nutrient deficiency, high temperatures, or harvesting too early. Some potato varieties will naturally grow smaller than others, and even the potatoes on one plant can vary in size.

15- Which fertilizer is suitable for potatoes?

Both potassium and nitrogen are needed throughout vegetative growth, tuber formation, and bulking. Potassium is the element most widely utilized by the potato crop and together with nitrogen is required in the highest quantities to achieve high potato yields.

Conclusion:

Potatoes are ready to harvest when the foliage begins to die back. The tops of the plants need to have completely died before you begin harvesting.