March Plant of the Month – Potatoes
Potatoes – Tips & Tricks for Great Growth
Congratulations we have made it to March. The calendar month of the start of spring! As I thought about the plant of the month on a cold snowy day I first thought of all the great tropical plants. But no, I’m ready to garden.
The first vegetables to go in the garden are the cole crops and potatoes. The cabbage, broccoli, and cauliflower are all grown from the plants we’ll have available later this month. They are planted and grown much like all other vegetables so I won’t go into a lot of detail here. Please contact me if you have specific questions. Potatoes on the other hand have some specific growing needs. I have included a portion of a good article from “The Potato Garden” on growing them.
Handling Your Seed Potatoes
Open all boxes upon arrival and leave open for air circulation. You may plant them right away or leave them at room temperature for a month or two. Find a cool place if longer and avoid drying conditions.
Here in a 40 degree cellar, your potatoes have been peacefully hibernating. Once taken out and shipped, they will warm up, break out of dormancy, and start growing. If your potatoes arrive with sprouts, handle them carefully when cutting and planting, leaving the sprouts on. But don’t worry if they break off because they will grow back. They just emerge faster when planted with sprouts in tact. If your potatoes arrive without sprouts, you can either pre-sprout them or plant right away in warm soil, 50 degrees or more.
Pre-sprouting Seed Potatoes
The practice of greening and pre-sprouting seed potatoes before planting, encourages early growth and hastens the development of marketable tubers. It is a method commonly used by growers of early potatoes in European countries but little used by American growers.
The method is simple: Spread the tubers in open-top crates, boxes or flats. The tubers are placed in the flats with the seed end uppermost, with usually only one layer to a flat. Bring the flats into a warm living space (70 degrees Fahrenheit) and to a location where the light levels are medium in intensity. The warmth tends to stimulate the development of
strong sprouts from the bud eye clusters, which, in the presence of light, remain short and stubby and are not easily broken off.
Usually seed potatoes are exposed to light and warmth a week or two before planting.
The benefits derived from greening and germinating the seed before planting are not limited to merely gaining a better stand and quicker maturity of the tubers, but it is claimed that a heavier yield is also likely.
Good potato soil will be well drained and, at the same time, able to retain moisture. Sandy loam is ideal. Other soils can be improved by incorporating organic matter which tends to lighten heavy soil and enrich sandy soil. Potatoes grow best in a soil pH of 5.0 – 7.5. Optimum soil temperature for beginning growth ranges from 50 degrees to 70 degrees Fahrenheit.
If your soil is compacted, you’ll want to loosen it up with a shovel, fork, or rototiller. With a shovel, don’t completely turn the soil over, simply dig a spot, with the shovel buried 8 to 12 inches and toss it back in. If you are incorporating compost, you can turn the soil a little more so that the compost is mixed in 6 to 8 inches. The idea is not to destroy too many of the beneficial soil microbes. However, for soils that are highly compacted, it is better to get the soil loosened up to a depth of 8 to 12 inches incorporating compost. The compost will be the start of another batch of beneficial microbes. If using a rototiller, you’ll want to work it in as deep as it goes. The long term goal for potato soil is to have a loose living soil full of beneficial microbes.
Cutting Seed Potatoes
All tubers the size of a hen’s egg (1-3 oz.) may be planted whole. For larger tubers, cut the potato using a clean, sharp knife so that each piece will contain 1 or more eyes. Pieces should be cut with plenty of flesh around the eyes, since the plant will utilize this stored food during the first 2 or 3 weeks of growth. If the variety has many eyes, try for two or more eyes on each piece. This provides opportunity for more vines to grow and thus yield more potatoes.
Seeds may be planted immediately after cutting if you have good control of soil moisture. If there’s a chance the soil may be too wet for a long period of time, you’ll want to allow the cut pieces to dry out prior to planting. Spread them out on a table in the shade or one layer deep in shallow boxes for drying. Avoid shriveling which may weaken the seed piece. Also recommended for wet soil conditions is the application of sulfur or Fir bark dust to the freshly cut pieces. Place 1 or more tablespoons in a large paper bag, and toss the pieces around to cover them with dust. This may guard against threat of infection by bacteria and fungus in wetter soil. If you are able to plant cut seed successfully, then there’s no reason to go through the extra steps of drying and dusting.
The rule of thumb to follow, for the earliest planting time, is to plant 2 weeks before your last spring frost. Then of course,you can plant anytime after that, giving yourself at least 3 months growing season before a major fall frost. Some growers plant later than this for better growing temperatures. Check with the locals. A good beginning soil temperature to plant in is 50 degrees Fahrenheit.
The width between rows is determined by the size of your garden and method of cultivation. Farmers need 30” -36” between rows, while gardeners can get by with 20” -26”. You might adjust your spacing to suit adverse conditions. Wider spacing can help alleviate stress due to drought or poor soil. Tighter spacing may give you a uniform canopy of foliage to cool the soil in summer.
Dig a shallow trench about 6” – 8” deep. Plant your seed potatoes about 12” apart. Using a rake, cover the seed pieces immediately after planting. Do not cover too deep, 4” maximum, and leave the remaining soil for later.
In approximately two weeks, depending on soil temperature, green leaves will emerge. When the plants have grown to about 8″ high, gently hill with soil brought up from both sides of the plant using a dull hoe. Bring the soil up about 3” inches leaving 4” – 6” of the plant exposed. Hilling cools the soil and creates
space for tuber development. All tubers will form at the same depth of the seed piece and higher. Another hilling of 1 to 2” is beneficial 2 – 3 weeks later. Keep the blade of your hoe well away from the plants so you do not damage the roots. If you see potatoes poking out of the hills, add more soil to cover them.
Hilling is crucial to establishing your crop. By gradually building an ever-larger hill of soil around the plant, you are building the site for your potatoes to develop. Give them plenty of room between rows and build your hills wide and ample to produce your bumper crop.
Raised Bed Method
Make your raised bed at least 12” deep and fill with soil. Plant seed potatoes 6” deep and cover to the top. If you are crowded, space them 8” – 10” apart in rows 20” apart. If you have room, plant 12” apart in rows 24” – 30” apart. Cover to the top. If you live in a wet climate, only cover to 4” deep so that the potatoes can get a quicker start. Then cover to the top later when the plants are tall enough.
Mulch Alternative Method
The Mulch Method is a good alternative if your soil is shallow, rocky or compact; if you’re planting in the heat of summer, or have problems with scab in your soil. The best mulch to use is loose, seed-free hay or straw. Leaves and dried grass clippings can be used. It is important to have plenty on hand.
Prepare your seed bed. Plant the seed pieces. They can be placed on the surface or lightly trenched, spaced as usual. Loosely shake mulch over the bed, 6″ – 10″ deep. As the plants grow, continue to add more loose straw, as if hilling. Be sure you keep the tubers well covered so that sunlight doesn’t get to them and turn them green. The mulching method provides excellent weed and moisture control and reduces stress due to heat. At harvest, pull back mulch. Your nest of potatoes will be clean, uniform and easy to harvest.
Cage Method Alternative
Grow potatoes in vertical boxes, cribs, barrels or wire cages. Set your cage on prepared soil. Plant strong seed pieces 6″ – 8″ apart and cover lightly with 4″ of soil. When the plant emerges and grows, begin adding mellow compost, mulch or soil always leaving at lest 6 inches of plant exposed. Continue this process until the plants stop their upward progress and/or blossom. Then let them finish out their growing season providing them with plenty of water. As the plant stems lengthen, so do the length and number of underground stolons, which are what produce the potato tubers. More potatoes form in less space and the
yield is increased 2 or 3 times. This is a great way to grow a lot of potatoes with limited garden space.
Weeding and Cultivating
Weeding is essential during this early part of the season. Using a hoe in a cultivating manner is a good way to check weeds when they are seedlings. Later, potato plants can canopy the soil and weed problems are slight. Pull out the ones that pop out. After hills are formed, mulch may be applied to retain moisture and suppress further weed growth.
Potatoes can be dry-land farmed where moisture retention and natural rainfall are adequate. However, if your summer is long and dry, your soil is sandy, or you would like to increase yields, you’ll want to water.
Potatoes need about 1” – 2” of water per week. Keep the soil evenly moist, but not too wet, from the time of emergence until then end of the season. Try not to let the soil completely dry out as this will cause sudden re-growth when watered, giving your tubers ears and noses, splits, or hollow heart. Each time you water, let it soak down 8” to 12”. A few thorough waterings, along with your efforts at hilling or mulching will be an adequate program to conserve soil moisture. Come up with a schedule, every three days or so, to check the soil moisture down at the roots.
Stop or slow down watering at the end of the growing season when plants turn yellow and begin dying. But make sure the soil does not completely dry out. You want some soil moisture but not as much as you had while the vines were drinking it up. Harvesting in drier soil is easier and potatoes are better cured and ready for storage.
Other than green manures, the best organic fertilizer for potatoes is good compost mixed into the soil the fall before planting. You may also mix in some compost before planting, however make sure it is done composting. Fresh manure will cause scab in the potatoes. Try to use compost that is 2 years old or more. The older the better. Adding compost to the soil is a good start for beneficial soil microbes.
The sugar in molasses is a good way to enhance the health of potatoes and the soil by feeding and multiplying the beneficial soil microbes. Fill a 5 gallon bucket with water and add one cup of molasses to soak for a day and night. Place the bucket in a hall or pathway so that you can stir it when you walk by several times that day. Apply the liquid molasses so that it soaks into the root zone of the potatoes. You can do this 1 to 4 times during the growing season.
Another benefit to increasing the population of beneficial microbes in your soil is that they will compete against the harmful soil fungus that causes scab. Amazing results!
Gophers can literally undermine your best potato crop. They are best kept in line by a strong patrol of hunting cats or dogs. Lacking that, trapping is effective. Good gopher traps can be bought at local feed stores. Several Jerusalem Artichoke growers have reported that the gophers prefer the Jerusalem Artichokes and will leave the potatoes alone.
The Colorado potato beetle is the most widespread and destructive potato pest. Both adults and larvae feed on the leaves and stems, sometimes defoliating entire plants. Hand picking is a fine control, if the problem is small and you catch it early. Pick into containers, then smash them all at once. Beetles overwinter in the soil, especially at the edges of the garden. Rotating your potato crop is essential!
Plan a trap: as early in the spring as you can manage, set out eggplants near last year’s potato patch. Beetles love eggplants, and over-wintering bugs will find your trap directly. Pick and destroy, and plant your potatoes later, in a new location.
I hope this helps you get your garden kicked off this season. Please contact me with any questions: firstname.lastname@example.org.