Your potatoes are planted, hilled and or mounded – now what do you do?
Potatoes will grow in 75 to 90 days for early varieties and 135 to 160 days for late yield varieties. There are over 1000 varieties and some of the best are White Rose, Norland, and Irish Cobbler for early ones; Superior and Russet for Mid Season varieties and Red Pontiac and Kennebec for the late comers.
Keep vines well watered especially after the vines bloom. A thorough watering once a week will be good. The tubers need water to swell into full potatoes. Water in the morning since disease can hit plants that are wet overnight. If your potatoes are hollow or centers are brown, you watered too much.
You can fertilize with a side dressing on either side of the trench a week before planting. Another way to fertilize is to use a liquid 5-10-15 fertilizer and spray it on before the vines bloom and you are done hilling. Only once a season is necessary unless the soil is severely depleted. Avoid a great deal of nitrogen. Nitrogen will make the vines grow but the aim is to focus on the tubers, not the vines.
Pull weeds by hand. Using a hoe to cultivate is dangerous since you can cut into a growing tuber by mistake or expose it to the sun.
Pests that affect potatoes are Flea Beetle, Aphids, and Colorado Potato Beetle. These pests are the biggest culprits when you see punctures or holes in the leaves of your vines. Wireworm and slugs feed on the roots. All can be controlled with insecticides from your local nursery. Just follow the directions on the labels.
Flea Beetles will appear as soon as the vines begin to grow. Small puncture holes will appear on the leaves. This beetle lays eggs on the backs of the leaves and the larvae move down to eat the roots.
Aphids voraciously eat leaves and they can be found on the undersides of them.
Colorado Potato Beetles have black and yellow strips and their eggs are in clusters colored orangish yellow. Check once a week and remove both from the leaves. You can also dust the tops of leaves with wheat bran. The greedy little bugs will eat it, bloat, and die.
All pests can be controlled by checking leaves every week. Treat with an insecticidal soap. Releasing lady bugs near your potatoes is a good way to control pests. They love to eat beetle eggs and aphids themselves. Also try planting garlic close to your potatoes. All of the pests hate garlic.
Diseases that can affect potatoes are early and late blight. Late blight is what decimated the Irish potato fields.
Early blight shows as circular brown spots somewhat like bull’s eyes on leaves. Good water management can prevent early blight. Brown or purple lesions on the leaves indicate late blight. The undersides of the leaves often have a white fungus as well.
Blights are fungal diseases and may be somewhat controlled by fungicides. Visit your garden center for an appropriate fungicide.
When the leaves of your potato vines start to turn yellow and die back in late August or early September, stop watering and don’t touch them for two more weeks.