How to seed potatoes?

How to grow: Potato

At a glance

Ease of culture: Moderate
Where: All regions
Best climate: Cool to warm conditions
When: Spring, summer, autumn in cool areas, winter in warm to hot areas
Spacing: 25-30cm
Harvest: 3-5 months
pH: 5-6


• Potatoes prefer cool mild conditions with daytime temperatures between 15-20° C
• They grow best in cooler areas, planted in spring (after last frost) and late summer/early autumn.
• If living in hot climates, grow through the cooler months – plant autumn-winter


• Find a spot with full sun (at least 6 hours per day) and protection from strong winds

Box: Seed Potatoes

Start your crop with the very best planting material. Don’t plant spuds bought from the supermarket or green grocer. Instead, plant ‘seed potatoes” that are certified virus-free. This avoids the potential of introducing a nasty virus to your soil and assures you the best potential harvest. Certified seed potatoes are available from nurseries and produce stores or try mail-order companies, where you’ll find the greatest range of varieties.

Preparing planting stock

• Expose seed potatoes to light (not direct sun) before planting to encourage them to shoot
• Large seed potatoes can be can be sliced to create more planting stock – just be sure each section has at least one shoot. Let them sit for a few days to allow the cut surfaces to dry before planting or they may rot.


The traditional way to grow potatoes is in the soil, but you can also grow them in containers or a no-dig garden.

In the soil

• Use a garden fork to loosen the soil to a spade’s depth, and then dig in plenty of compost or well-rotted manure – at least 2 bucketfuls per square metre.
• To improve drainage, mound the soil in planting rows with centres 40-50cm apart
• Dig narrow trenches along the centre of the mounds 10-20cm deep
• Place seed potatoes along the trenches 25-30cm apart, shoots facing upwards
• Cover the seed potatoes with a 10cm layer of soil and water in well.

Box: Hilling for better returns

As the potato shoots begin to grow above the soil surface, gradually cover them with soil. This process, known as hilling, encourages the plants to form more roots along the buried stems on which more potatoes will form, increasing overall yield.

No-dig method

• Find a spot in the garden where the ground is well drained
• Mark out a growing area – 1.2m x 1.2m is a good size to start, or go bigger
• Cover the area with 6-7 sheets of newspaper, overlapping the edges to smother the weeds and grass. Wet it to stop it blowing away.
• Place your seed potatoes on the surface, 25-30cm apart.
• Cover the potatoes with thin layers of compost, and other organic materials like well-rotted manure, sawdust, old grass clippings, and dry leaves – whatever you’ve got. Water each layer as you build it up to a final depth of 20cm.
• Add more layers as the potatoes grow and the materials break down. After a month or so, add a final layer of straw 10-15cm thick.

Container method

• Choose a big container – at least 30cm wide and deep – the bigger, the better.
• Plastic pots are good, old laundry tubs, wheel barrows or even old hessian bags – whatever you choose, ensure it has adequate drainage holes.
• Prepare your growing medium. Potting mix is okay, but a 50/50 blend of potting mix and compost is better.
• Tip a 10cm layer of growing medium into your container, then lay your seed potatoes on the surface, 25-30cm apart, with the shoots pointing upwards.
• Cover the seed potatoes with another 10cm layer of growing medium and water the mix well.
• As the shoots develop, gradually cover the stem with more mix – up to an additional 40cm deep.
• Finally, cover the mix with a mulch of straw to help hold in moisture

Watering and fertilising

• Attention to watering is critical. Lack of adequate moisture with result in a poor crop whereas too much water will cause tubers to rot. Maintain a regular soil moisture level – it should feel slightly damp to touch, not soggy.
• Fertilising your potato crop will provide better returns. Give plants a light application of an all-purpose organic fertiliser after planting. Follow up with another application after six weeks.


• You can start to harvest potatoes any time after about 8 weeks, by digging around plants while they’re still growing and grabbing a few new or small potatoes.
• The longer the plants are left to grow, the bigger the potatoes will grow.
• The best time to complete harvesting is when the tops have died down – and no more tubers will develop.
• Use a garden fork to gently loosen the soil to reveal the potatoes – be careful not to stab them
• Let them dry on the ground before brushing off excess soil ready for storing (do not wash them – this shortens storage time)
• Store in a dark airy space
• Eat damaged spuds first.

Peffley – Make your own seed potatoes.

It is still early to sow seed for summer gardens but it is potato-planting time.

The potato is an interesting vegetable. The potato, tomato, pepper, tomatillo and eggplant are all members of the Solanaceae family but the potato is quite different as it is the only Solanaceous crop for which the edible portion is an underground part. The scientific name of the potato is Solanum tuberosum, so named because it is botanically a tuber, a swollen enlarged underground stem, and not a root.

Potatoes are propagated from vegetative structures called “seed potatoes” rather than from true seeds harvested from floral structures. True potato seed are tiny, rare, difficult to mature and are used as breeding material for the development of new varieties.

Establish potato crops using certified seed potatoes purchased locally from nurseries, home improvement centers, catalogs or they can be made at home.

To make your own seed potatoes select healthy, non-diseased, firm tubers and with a clean, sharp knife cut the tuber into pieces. Optimal sized-pieces are 1½ to 2 inches in diameter, blocky or square in shape, with as few cut surfaces as possible and containing at least one bud eye in each piece.

Buds in the eyes of potatoes have multiple vegetative structures, and it is from these buds that stems and roots will be produced and develop into the new plant.

Seed pieces may have buds developing sprouts, such as those in the photo, or may have buds that are still dormant. Pieces taken from tubers that were sprouting when cut should be planted immediately after cutting. Seed potatoes that have sprouting buds when planted usually produce larger crops since sprouts are already present on those pieces and plants will emerge from the ground more quickly.

If several shoots arise from one eye, eliminate all but one before planting because stems developed from multiple sprouts will compete with the result of smaller tubers at harvest.

Tubers cut into seed pieces that have dormant buds should be cured before planting by placing on newspaper in a cool dark spot for a day or two. During the curing process corky, roughened cells known as suberin form on the epidermal layer of the cut surfaces.

Suberin is the same corky tissue that is found on the outer epidermis of commercial potatoes. Suberin protects seed pieces from drying out and shriveling after planting and protects against soil-borne, disease-causing pathogens that will cause seed pieces to rot.

Plant potatoes after danger of hard freeze in full sun. Till the ground to a depth of 12 inches, amend heavily with organic matter; place seed pieces eyes up and mound soil into hills. Space every 12 inches with rows 36 inches apart. Keep soil moist. Tubers are ready for harvest when tops die back in late summer. Potatoes planted now should be ready for harvest July 4.

ELLEN PEFFLEY taught horticulture at the college level for 28 years, 25 of those at Texas Tech, during which time she developed two onion varieties. She is now the sole proprietor of From the Garden, a market garden farmette. You can email her at [email protected]

Grow your own Seed Potatoes

15th January 2017

Grow your own Seed Potatoes

There are a vast amount of varieties available to cater for every culinary need, and by staggering your planting you can prolong your harvest period from May, all the way up until November.

Potatoes are grown from small tubers called ‘seeds’, which look like small, soft potatoes which sometimes have ‘eyes’ on. These are the spots from where the green stems grow.

There are four main types of seed potato available:
Salad potatoes: Known for their firm, waxy flesh and unique flavour, these are ready relatively early in the season.
First Earlies: These are the very first potatoes to be ready in the year, maturing from as early as May when planted in February. These are often known as ‘new potatoes’.
Second Earlies: These follow-on from the first-earlies and are usually ready to harvest from June as well as being suitable for storing until August.
Main crop: Ready to be lifted from September to October, these can be eaten straight away or stored for up to three months.

Preparing Potatoes
To get your potatoes off to a flying start it is often recommended that you ‘chit’ them before planting. This allows stumpy but strong chits (sprouts) to develop on the tubers before planting. Whilst this process is not essential for main crop varieties, it is strongly recommended for First Earlies and, to a lesser degree, for Salad varieties and Second Earlies.

To chit seed potatoes, place them just touching in a seed tray or individually in the sections of egg boxes. Make sure the ‘rose’ end (where most of the ‘eyes’ are) is at the top. It is these eyes that will form the chits. Place the trays in a cool, light frost-free environment at a temperature of about 7°C (45°F).

The aim of chitting is to produce plump, dark green or purple shoots about 2.5cm (1in) long. Thin, long white shoots are a sign of too much heat and not enough light. If shoots are slow to appear, about 3 weeks before planting move the tubers to a warmer position for a couple of weeks and then back to the original, cooler place for the final week.

Planting Potatoes
When to plant

Salad potatoes: March – April
First Early potatoes: February – April
Second Early potatoes: March – May
Main Crop potatoes: March – May

Potatoes grow well in most soil types but ideally they should be grown in well-drained, loamy soil that is not too heavy. The soil needs to be deep, well dug and with plenty of well-rotted organic matter incorporated. The plot should be cleared and dug over in late autumn/early winter so that the frost can break down the soil structure, which will make for easy planting in the spring. Alternatively, you can successfully grow a good crop of potatoes in Gro-Sacks.

Ideally, potatoes should only be planted in the same part of the garden once every 7 years but, given that this is not practical for the vast majority of gardeners we recommend a minimum of 3 or 4 years.
Set the tubers in rows, either at the bottom of a ‘V’ shaped trench or in individual small holes made with a trowel. Many gardeners aim to have the rows running north-south as this allows the sun’s rays to warm both sides of the ridges.

First Earlies, Second Earlies and Salad varieties should be positioned 30cm apart and 10cm deep in rows 45cm (1 ½ ft) apart; Maincrop varieties should be spaced 40cm (16in) apart and 10cm (4in) deep in rows 60cm (2ft)apart.

As soon as shoots start to appear above the soil, it’s time to start ‘earthing up’ the rows. This means pulling soil over the shoots from either side of the row to form a ridge. This protects the plants from late frosts and prevents the tubers from becoming green and inedible. Repeat this regularly until the ridges are about 20cm high.

Feeding Potatoes
Planting in loamy soil will give the intital nutrients the seed potatoes require. Just before planting fork in a general purpose fertiliser like pre-planting potato feed.
After that you want to avoid fertiliser that is high in nitrogen which affect the maturity of the crop. An application of a high potash fertiliser at the rate suggested on the pack will increase yields, our Bio-Gro Black Gold fertiliser is ideal.

Watering Potatoes
Planting in loamy soil is also good for the underground potato crop. The loam crates a soil structure that keeps the soil moist. This is just as well, as potatoes are thirsty plants.
Potatoes need plenty of moisture, particularly round about flowering time which is when the tubers start to form. In dry spells it is recommended that the crop is watered every 10 days or so. An occasional heavy watering is better than little and often as this does not get down far enough and encourages shallow rooting.

Temperature for Potatoes
If you can grow your potatoes in a light, warm, sunny spot, where they’ll thrive especially if growing in rich, loamy soil.
Avoid planting in areas prone to frost. If you do hear there’s a frost due, cover the plants with a double layer of horticultural fleece to protect them. Blackened stems is a good sign growing potato plants have been pinched by frost. They can usually tolerate a one-off frost-attack, but certainly not anything more frequent.

Harvesting and Storing Potatoes
Harvest times depend on planting dates, weather and temperature at planting time, weather during the growing season, variety maturity and weather and temperature at harvest time.
First Earlies are best harvested in small quantities and eaten straightaway when fresh in April and May. Harvest when the potato flowers are open.
Second Earlies and Salad varieties can also be harvested in small quantities and eaten when fresh in June and July. Harvest when the potato flowers are open.
Maincrop varieties can be lifted from September onwards. Harvest once the leaves have yellowed, remove the leaves and harvest a week later. They can be stored as long as the potatoes themselves are lifted in dry conditions or are dried properly before being put away. Store in a hessian sackin a cool, dark, frost-free area.

Pests and Diseases of Potatoes
Potato Blight – Worst in warm, moist conditions from mid-summer onwards. Brownish black spots appear on leaves and stems and eventually spores from these spots can wash into the soil and effect the tubers. You can reduce risk by wide spacing or growing in Gro-Sacks, as this reduces the risk of infection from one plant to another. Remove and destroy effected leaves and leave the potatoes in the ground for three weeks before lifting, so that the spores on the soil surface die.

Potato Cyst Eelworm – This is a widespread problem in soil where potatoes are often grown. The plants’ growth is stunted and the leaves turn yellow and die. Your yield of potatoes will also be reduced. Unfortunately there isn’t a lot that can be done about eelworm, apart from to avoid growing potatoes in affected areas. One way of making sure you’re not planting potatoes in eelworm-affected ground is to plant them in Gro-Sacks with fresh compost.

Virus diseases – Potatoes are susceptible to several aphid-borne virus diseases. Leaves become mottled and the plants stunted. Any diseased plants should be lifted and destroyed. Preventative measures include: buying new seed rather than saving your own, bin old tubers instead of adding them to the compost heap.

Potato Blackleg – Leaves become pale and curly inwards and the stems begin to rot at the base. Affected plants should be dug up and destroyed.

Common Scab – Scabby areas develop on the potatoes themselves, but is mainly a cosmetic disease.

Slugs – slugs can eat the leaves which can stunt the growth of tubers under the ground. Keep the slugs at bay with Eraza Slug and Snail Killer.

Potatoes are one of the easiest and most productive backyard crops. Plant in late winter to early spring, but if you are planting early remember that potatoes are susceptible to frost, so once their tops have come up, they will need protection on frosty nights.
Cut your potatoes into pieces (each chunk must contain an ‘eye’) at least a day before planting to allow the cut surface to seal. After the initial watering-in, don’t water until the shoots have appeared, and then only enough to keep the growing medium just moist. Once tubers begin to form, it is key to prevent them being exposed to any sunlight, which will turn them green and toxic. This is one reason for all the mounding of soil and layering of straw you are about to read about, but the other reason is that more and more potatoes will form along those stems you have covered over, enabling harvests of up to 7kg per potato planted!
Harvest your potatoes once the plants have started to yellow and wither (14-16 weeks) – this is essential if you want to store them, as their skins will have reached full thickness by then. Otherwise you can have a sneaky feel around in growing medium, and gently pull out a few early ones after 10 weeks or so.
In-ground growing
Dig 20cm deep trenches into loose organic matter-rich soil, and drop a spud chunk in every 40cm. Rake the soil back over to cover, top the whole area with a 5cm layer of well-rotted manure (sheep is perfect), and ideally add a handful of blood and bone mixed with a heaped spoonful of potash per square metre. Cover with a 2cm layer of straw mulch and water in well. Once the tops are up, usually in about 3 weeks, you can either hill up the soil from between the rows to cover them, topping with another layer of straw to prevent the soil washing away, or simply cover the whole lot with more straw mixed with some more manure (instead of manure you could use compost mixed with a sprinkle of blood and bone).
On-ground growing
Essentially as above, but instead if digging trenches, you start by mowing any grass or weeds (leave them where they fall), and laying down about 6 sheets thickness of wet newspaper on top them. Place your potato chunks at 40cm spacings over the area, and cover them with about 50cm thickness of straw. Top this with the same layers of manure, blood and bone and potash as above, but in this case the blood and bone and potash are much more important, as they will aid in breaking down the straw into a perfect potato growing medium. Water in very well. Once the tops appear, spread another 5-10cm of straw about. This method has the advantage of being able to lift up the corner of your straw carpet to steal early potatoes, of providing you with nearly clean soil-free potatoes at harvest time, and of leaving the soil in the growing area in wonderful condition.
Container growing
A large pot, an old bath tub (with added drainage holes), a half wine barrel, a hessian sack, or a cylinder of fine-mesh chicken wire all count as containers. Provide a 20cm bed of soil to put your spuds on, and layer as above, using any mixture of soil, straw, manure etc., keeping in mind to balance straw and manure to provide good nutrition. The advantage here is that you can easily keep covering the tops as they appear right to the top of the pot, maximizing your harvest (if using a hessian sack start with it rolled down, then simply roll up the edges as you continue to fill it).

Potato Planting Preparations

Note: Several readers have requested posts on topics that have already appeared here – pre-sprouting & cutting seed potatoes is one of those posts that has been updated and republished.

I used to think that growing potatoes in the garden was too much work for the end result. Then a friend’s homegrown Yukon Gold potatoes completely changed my mind. Like almost anything that’s homegrown, they just tasted so much better than potatoes from the grocery store.

That’s when we started growing our own potatoes and found that in addition to tasting much better than store bought potatoes, they were really an easy crop to grow. And, that many varieties store well in the root cellar so we could have great tasting potatoes nearly year round.

Now, we grow potatoes every year and our potato planting preparations include pre-sprouting (also known as greensprouting) & cutting seed potatoes. These practices encourage early growth, improve yields, and speed up production of tubers.

Fast, early growth is beneficial when growing potatoes. If you can get them in, grow them quickly, and get them harvested fast there’s less chance that pests (see Controlling Potato Beetles) or bad weather will damage your crop of potatoes.

Pre-sprouting & cutting seed potatoes means a few extra steps but they take just a little extra time and can significantly improve productivity.

How To Pre – Sprout Seed Potatoes

We purchase certified organic seed potatoes (for example the organic seed potatoes from Wood Prairie Farm) early in the season when there is a good selection of varieties, and keep them cool (40 degrees) in a dark root cellar until about two weeks before I intend to plant them. Potatoes shouldn’t be planted until the soil temperature reaches 50°F. The varieties shown in the photos below are Yukon Gold and Purple Viking.

Then I spread them out on a tray in a room with medium light and 70-degree temperatures. The warmth promotes the development of strong sprouts, and the light causes the sprouts to stay short and stubby (not weak or easily broken off). This step adds a little more work, but results in quicker tuber development and also heavier yields.

Unsprouted Seed Potatoes

The photo above shows the whole seed potatoes prior to pre-sprouting while the photo below shows them after pre-sprouting. Pre-sprouting or greensprouting can reduce the time to mature potatoes in the field by 10 – 14 days. We pre-sprout the entire potato crop since we have a fairly short growing season and we use every method we know to get the crop in and grown quickly.

Pre-sprouted Seed Potatoes

Even if you don’t pre-sprout your seed potatoes, simply warming the seed potatoes up before planting will be beneficial. Warming the seed potatoes at 70°F for 48 – 72 hours before planting will improve germination rate and yields too. Don’t plant cold potatoes!

Cutting Seed Potatoes

Small potatoes (the size of a small egg) can be planted whole, but larger potatoes should be cut into smaller pieces. The ideal potato seed is a 1 1/2-ounce block with two or more eyes/sprouts per seed. Therefore, larger seed potatoes should be cut into 2, 3, or 4 blocks per tuber.

After cutting, the seed pieces should be left at room temperature for at least twenty-four hours, allowing them to firm up and reduce the chance of rotting. To further minimize the chance of rot, the cut surfaces can be dusted with calcitic or dolomitic agricultural lime or sulfur. After twenty-four hours, I plant them using the “Lazy Bed Potato Planting Method”.

Seed Potatoes After Cutting

We’ve found that by using these methods for preparing the seed potatoes for planting, using the lazy bed method for growing the potatoes, and making sure that we ALWAYS rotate the potato crop (see Garden Crop Rotation – A Simple System) potatoes are a really easy and productive crop for us to grow each year.


1. Q: I used potatoes purchased at the grocery store as seed for planting and they rotted without sprouting. Why?

A: Many potatoes sold for fresh market consumption have been treated with chemicals to prevent sprouting in storage. These chemicals will also prevent sprouting after planting. Another possibility is that the potatoes that you purchased in the store were from this year’s crop and had not been stored properly to break the rest period. Potatoes have a rest period which must be broken before the seed will sprout. Cool temperatures or extremely warm temperatures can break the rest period and allow potatoes to sprout. Next time plant certified seed that has been properly stored to induce sprouting.

2. Q: Can I save the small potatoes from my spring crop for planting in the fall in my garden?

A: Yes. This is commonly done because good seed potatoes are scarce in the fall. Sometimes the potatoes saved from the spring garden fail to sprout when planted in the fall because of a natural dormancy in newly harvested potatoes. Considerable controversy exists as how to handle these potatoes in order to break the dormancy and enable them to sprout when planted. One recommended procedure for breaking the dormancy includes harvesting the potatoes and placing them in a cool storage area, preferably in the range of 50 degrees F. until about 3 to 4 weeks before the anticipated fall planting date. At that time, remove the small potatoes and maintain them at normal environmental conditions until planting time. Maintaining the seed potatoes at a high humidity during this time by covering them with moist burlap bags or some similar material will also initiate sprouting. The small potatoes should be planted whole and not cut to prevent rotting.

3. Q: What size piece should seed potatoes be cut into?

A: Each seed piece should contain at least 2 to 3 “eyes”. Research has shown that the best size seed piece weighs approximately 2 ounces.

4. Q: Sometimes my potatoes or the potatoes I see at supermarkets have a green color. Are these potatoes poisonous?

A: Potatoes that exhibit a green color contain a substance known as Solanine. This substance, if consumed in extremely large quantities can cause severe illness or death. This greening of potatoes is caused by exposure to light during the growing period or excessive exposure to artificial lights at grocery stores or supermarkets. In the garden, this is most common after heavy rains which uncover potatoes near the surface exposing them to sunlight.

5. Q: How do I know when my potatoes are ready for harvesting?

A: Potatoes are generally mature when the plant starts to turn yellow. Potatoes require 75 to 140 days from planting to maturity depending upon variety and the season in which they are grown. Immature potatoes will often skin and bruise easily. When digging potatoes, if the skin is not set and is easily removed, delay the harvest. Dig spring-planted potatoes before the soil becomes hot. Avoid harvesting the potatoes when the soil is wet to avoid potato diseases.

6. Q: I have some seed potatoes left from my spring garden. Would it be all right to eat them?

A: No. Potato tubers purchased for seed purposes definitely should not be eaten. Frequently, such tubers have been chemically treated. Like all treated seeds, seed potatoes should not be fed to humans or animals.

7. Q: After harvesting, how should I handle my potatoes to result in the longest storage time possible?

A: Dig potatoes when the soil is dry, being careful not to skin or bruise the tubers. Do not wash the potatoes. Place them in crates or some suitable container and store them in a dark area for about 10 days at a temperature of 60 degrees to 65 degrees F. with a relatively high humidity. After this curing period, keep the potatoes at 40 degrees to 45 degrees F. with the humidity near 85 percent and provide good air circulation.

8. Q: Can potatoes be left in the ground for storage?

A: Generally, no. Cool, humid conditions (38 degrees to 45 degrees F., and 85 percent relative humidity) are best for Irish potato storage. Leaving the potatoes in the ground with a heavy mulch to keep the soil cool will provide good temporary storage if the soil is not saturated and is free of wireworms and grubs. The potatoes would not stay dry enough in the soil to prevent second growth or sprouting. Several weeks at high temperatures can break the rest period in home-grown potatoes after which sprouts will develop on the tuber. All things considered, it is better to dig the potatoes and put them in a cool, damp area.

9. Q: Why do home-stored potatoes have a different flavor in the winter than in the summer?

A: Irish potatoes stored at temperatures below 55 degrees F. will taste sweeter and be stringier than those stored at warmer temperatures. At temperatures less than 55 degrees F., enzymes within the tuber convert starch into sugars causing the sweet taste and stringy consistency. Potatoes to be eaten should never be stored in the refrigerator. Sugars within the potatoes can be converted back into starch by storing the potatoes at temperatures above 65 degrees F. for a week or two prior to use. Some gardeners store potatoes in large lots in cooler temperatures to keep them from sprouting and keep a small quantity inside their house for immediate consumption.

10. Q: My potato plants produced small tomatoes this year. I planted them next to my tomatoes. Could they have crossed or have my potatoes mutated?

A: The fruit on the potato plant is actually the fruiting structure of the potato plant. The potato and tomato belong to the same botanical family and have similar growth characteristics. The potato flower looks very much like the tomato flower and is pollinated and fertilized identical to the tomato flower. The fruit will mature if the plant is left long enough. Your potato and tomato plants have not cross fertilized.

11. Q: What is a “Topato” which is advertised in gardening publications?

A: The Topato is a patented name used by a company to describe a plant which supposedly produces tomatoes above ground and potatoes beneath the ground. If a Topato is ordered, you will receive several potato seed pieces, a few tomato seed and usually a razor blade with instructions as to how the Topato should be planted. This generally consists of hollowing out the potato seed piece, placing several tomato seed in the hollowed out area and planting the result in your garden. If it germinates and grows, the result is both a tomato and a potato plant above and beneath the ground. It will not be a cross, one plant with the ability to produce tomatoes and potatoes, but will be two individual plants producing normally.

12. Q: The stems of my Irish potato plants are decayed. The plants weaken but do not die.

A: This is Rhizoctonia. It is a soilborne fungus that causes decay in stems and seed pieces. Approved seed-piece fungicides are the best of control. Follow the label instructions closely to get maximum control.

13. Q: After a rainfall, the plants in one area of my garden began to die rapidly. The stems were rotted. A dark discoloration is moving up the stem to the top of the plant, and the stem has a foul odor.

A: This is black leg of potatoes, one of the major bacterial potato problems. To avoid this, plant only in well- drained areas. Seed piece treatment will also help prevent the entry of bacteria and other organisms.

14. Q: When I dug my potatoes, they were covered by small, raised bumps.

A: These are root knot nematodes. They are a serious problem on potatoes.. Root knot is a species of nematode which causes galls or swellings on plant roots. It restricts the uptake of nutrients from the root system to the foliage, resulting in a yellow and stunted plant. Root knot lives in the soil and can survive on a number of weed and vegetable crops. It is best controlled by planting a solid stand (close enough for root systems to overlap) of marigolds three months before the first killing frost of fall and/or planting cereal rye (Elbon) for a winter cover crop. Cereal rye should be shred and tilled into the soil 30 days before planting a spring crop. Also, rotate where nematodes have become a major problem.

15. Q: After I dug my potatoes, I found that they were rough with deep scars.

A: This is potato scab, caused by a soilborne organism. To control this, maintain an acid soil around your potato plants. Maintain a uniform moisture level from the time the potato is formed until it is harvested. Seed-piece treatments have proven somewhat effective in preventing this problem.

16. Q: The lower foliage on my potato plants is beginning to turn yellow and is covered with brown spots.

A: This is early blight of potatoes and is similar to blight on tomatoes. Spray with chlorothalanoil-containing fungicide as soon as spots are observed and repeat at 7- to 14-day intervals for two to three sprays.

17. Q: The foliage of my potato plants is distorted, rolled and is not as thrifty as it should be.

A: Several viruses attack potatoes. The best prevention of potato viruses is to plant only certified seed pieces.

18. Q: When I dug my potatoes, I noticed small holes chewed in the potato. How do I prevent this?

A: Several soil-inhabiting insects such as wireworms and white grubs cause this type of damage. Use control measures for these pests before planting. Diazinon is effective on soil pests. Use as directed on the label.

19. Q: The leaves of my potatoes are disappearing fast. All I see on the plant is some pinkish worms.

A: These pinkish larvae are immature Colorado potato beetles. They can defoliate plants and should be controlled with Sevin, Thiodan, or methoxychlor. Use as directed on the label. In small plots, control by hand picking the larvae and destroying them.

20. Q: Is the potato the most popular vegetable in the world?

A: The potato is not the most popular but certainly the most important.

When Europe’s 15th century explorers went looking for the riches of the East, they found the West. They also came upon a treasure that would ultimately prove to be more valuable than gold or spice: the potato. However, not until the middle of the 17th century, when Frederick William of Prussia planted them in his garden in Berlin, was any effort made to even grow potatoes in Europe. And it took even longer for the spud to find its place on the world’s tables. That didn’t happen until Frederick the Great began distributing them to the poor 100 years later.

It was a Frenchman named Parmentier who was the potato’s biggest booster. Parmentier developed a taste for them while a prisoner in Germany, and upon his release, returned to France with a bag full of them that he used to cultivate more. His first crop was such a success that he presented a bouquet of creamy potato blossoms to his king. Louis XVI, who stuck a single flower in his buttonhole and gave the rest to his queen, Marie Antoinette. She, in turn, appeared at dinner with potato blossoms worked into an elaborate coiffure. That’s all it took. France quickly adopted the potato, and soon the lowly brown tuber was bubbling away in pots all over the country. “France will thank you some day for having found bread for the poor,” Louis XVI told Parmentier. And so it did, naming the now-classic French potato soup potage Parmentier.

21. Q: Can I save the small potatoes from my spring crop for planting in the fall in my garden?

A: Yes. This is commonly done because good seed potatoes are scarce in the fall in Texas. Sometimes the potatoes saved from the spring garden fail to sprout when planted in the fall because of a natural dormancy in newly harvested potatoes. Considerable controversy exists as how to handle these potatoes in order to break the dormancy and enable them to sprout when planted. One recommended procedure for breaking the dormancy includes harvesting the potatoes and placing them in a cool storage area, preferably in the range of 50 degrees F. until about August 1. At that time, remove the small potatoes and maintain them at normal environmental conditions until planting time. Maintaining the seed potatoes at a high humidity during this time by covering them with moist potting mix or compost material will also initiate sprouting. The small potatoes should be planted whole and not cut to prevent rotting.

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