The DTE Notebook for the Urban Organic Vegetable, Herb and Flower Gardener.
Potatoes: the good, the bad, and the ugly
Article and photos by Rob Danforth
Potatoes: the “good” (3.5 lbs from 1 store bought potato), the “bad” (Colorado Potato beetle and sun kissed potatoes), and the “ugly” (potato scab).
You can buy organic seed potatoes or you can salvage that forgotten potato in your pantry – the one that has gone soft and is “chitting” (aka “sprouting”). When moisture or ethylene gas is in close proximity to potatoes (e.g., moisture from onions stored near potatoes or gas from nearby maturing fruit), the potatoes will get soft and a bit spongy and the eyes will send out white or yellowish shoots called chits. This is worth knowing in case you want to deliberately chit potatoes in time for planting.
Cut this chitted potato into chunks with a sprouting chit in each chunk. The size of the chunk does not matter so no need to make them all the same size. We planted 21 such chunks in a 4×8 box bed along with chard and parsley for a long-term care facility and all were successful.
Plant the chunks in a plot, box bed, or potato bag with the chit facing upward. Planting your chunks in the bottom of a saucer shape can leave you room to hill soil around the plant as it grows. Planting in a potato bag for deck, balcony, or patio lets you roll down the sides of the bag to start the plants and then roll up the sides gradually as the plants grow and you continually add soil until you run out of bag (about 2 feet high).
Hill the potatoes to be sure no potatoes are peeking out of the soil because the sun will cause problems.
As soon as the plants flower, remove the flowers and let the plants grow on. Seed production requires a lot of energy which you would rather have applied to the potatoes.
Let the stalks turn yellow and die back, cut the stalks 6 inches above the soil and leave for 2-3 weeks. The earlier you trim the stalks, the smaller the potatoes.
The Colorado potato beetle favours the potato plant, but also likes eggplant, tomatoes, and peppers. If you plant early, be sure to use poly tunnels or row covers immediately. Potatoes do not need their flowers pollinated so you do not need to uncover them until much later, except to check periodically to be sure you are not setting up a bug incubator for any bugs trapped inside the covers.
If you are too late covering the plants, then you have to check each plant to squash the orange eggs on the underside of leaves, the fat, tawny grub like adolescents and the brown and white striped adult beetles. Left unchecked they will defoliate your potato plants and you will have what looks like an umbrella without the fabric cover. One year I planted early but I was a day late covering 10 plants. I had 3 weeks battling bugs to save the plants. You must squash the adults or drown them in a cup of soapy water or you can spray the eggs and adolescents with soapy water and then rinse each plant with clean water after 10 minutes. Do not leave soapy water on the leaves.
For spraying, it helps to have a spray gun that is not screwed to the top of the spray bottle. A spray gun on a 2 or 3-foot tube which is inserted through the cap and into the bottle allows the bottle to stand flat on the ground and the spray gun to be turned in any direction to get at the underside of leaves. You can make your own with recycled materials, or purchase one at a dollar store.
Repeat your bug fight every 3 days for up to 3 weeks until the problem has been solved. Do not give up; you will eventually win. Note: if your potato plants have attracted Colorado beetles, be sure to check your tomatoes, peppers, and eggplants. Same battle strategy applies to these plants as well.
If you are limited to weekend gardening, then plant potatoes in mid-June to avoid the Colorado bug traffic.
I have seen a week’s worth of devastation on 25 potato plants – the weekend gardener was in tears at the loss of his plants.
If the potatoes are slightly exposed to the sun, the exposed area will turn green. This green part of the potato is toxic for people. Cut away the green and eat the potato.
Potato scab is very unsightly and off-putting, not to mention the foul smell of rotting potatoes. Apparently, you can cut away the scabs – some are deep – and eat the potato (I don’t), but the look of them may take away your appetite. The scab is formed by bacteria in the soil and garden soil can create conditions for potato scab if there is too much moisture retention. You will not know it is happening until you harvest the potatoes. The solution is to plant potatoes in an acidic soil with a pH value of 6, or even 5. Bacteria will not thrive in acidic soil. If you add compost twice a year (fall and mid-summer) this should regulate the acidity and you can also add pine needles, used tea leaves, and even the dregs of tea (no milk or sugar) from a teapot, to help add acidity (also good for roses).
Do not use vinegar or citrus.