20 Apr 23 Benjamin Chapman (Australia - temperate climate)
I understand that "non specific" potato varieties don't need the soil to be mounded up as they grow.
Where can I find a list which shows "specific" and "non-specific" potato varieties.
06 May 23 Celeste Archer (Canada - Zone 5a Temperate Warm Summer climate)
Technically you don't HAVE TO HILL any variety of potatoes. Here's how it works: you plant the seed potato (which is an extra small potato saved/stored from last year's harvest -- or a piece of a larger potato that you stored/saved from last year) -- the DEPTH THAT you PLANT that SEED POTATO determines your LOWEST POINT -- GENERALLY, and I do mean GENERALLY (like 95% of the potatoes) the potato plant will not create tubers LOWER than the depth you planted the seed potato at (so your seed potato is the BOTTOM of the plants tubers/potatoes). Which is why some people think the very bottom potato always rots, when in reality it is the seed potato and is expected to grow and will appear rotten. Which means if you don't hill up as your potato plant grows and you planted the seed potato shallow, there is not that much ROOM for the potato plant to put it's tubers, and larger tubers will usually "pop" out of the soil and turn green due to sun exposure. If you don't want to hill up, plant your seed potato deeper than recommended -- yes it will be fine -- the reason you plant shallow and mound up is because the potato plant will be able to get leaves into the sun sooner if it's seed potato was planted shallow, which means it will grow quicker because it is collecting light sooner -- then you mound up to offset that you planted the seed potato shallow, but you always leave lots of leaves exposed to the sun so the plant can collect sun and grow. It's a lot of extra work work to mound up soil-- and maybe speeds up the process "brings in the harvest" by 10 days or so.... My experience is planting seed potatoes a foot deep ((30cm) is fine -- yes the plant takes a little longer for it's leaves to surface -- but it's fine and you should not experience any problems - provided the soil is nice and loose. (hopefully that makes senses). I think in the future I will plant two potatoes side by side -- one deep, one using the mound method and record the progress and final outcomes... I have never done a tandem planting -- BUT I HAVE had potatoes spring up from deep down Once as I dug out one of these "self planted potatoes" I realized it was down about 30" (70cm) -- it was in a potato planting tower (old full size garbage can full of 3" holes all over) which I dumped and collect the potatoes from the year before, then just put the soil back, week by week, as I composted kitchen scraps directly into the soil... so no surprise that a potato was so deep -- it grew -- it put out potatoes and it's crop was average good... it spent a lot of energy growing up -- and perhaps I harvested too early based on the other potatoes-- but it made it and did OK, good size potatoes, good quantity. I would not recommend placing your seed potatoes that deep, but a foot (30cm) should be fine.
03 Nov 23 Scott (Australia - sub-tropical climate)
The other reason to hill potatoes is that the plant gets quite tall and top heavy. This makes it susceptible to getting blown over by wind. This will cause the plants to die off early. If you hill it mid season you stop the plant from blowing over and you increase the size of the potatoes as they have had longer to grow and mature.
I heard that the potato will stop sending nutrients to the tubers if the stalks are bent.
One of the most successful potato harvests I have ever seen was a large container grown project where he used several layers (think of a layer cake) of horizontal plastic fencing and t-posts at each corner to hold the horizontal fencing to keep the stalks from bending at all and support them as they grew. They were able to get an absolutely massive yield with that method although he was sick all summer and didn't care for them or water them at all. I am not sure that the container growing was as pivotal in the results as just keeping the stalks from bending over. I have container grown before and will try it again this spring as well as ground growing using his methods to keep the stalks upright.
I think another often overlooked issue is either too much or too little phosphorus and potash in 10-10-10 fertilizer. I think 'balanced' fertilizers can present real problems for root crops since they don't need or want balanced inputs. You will always have too much of something and too little of the other. Also there is a time delay on phosphorus while it stays in the upper part of the soil, so you can apply phosphorus to increase tuber formation, but it takes 3 months to disperse into the soil, while nitrogen sinks like a stone through soil an becomes almost immediately bio-unavailable (or runs off into the environment via water). So if you are using 10-10-10 you are going to end up poisoning your plants in order to get one or another nutrients available in the correct quantity. Plus factor in the time delay to bioavailability.
I think it is better to thoroughly prepare soil before you put your garden to bed in the winter than prepare it in the spring (actually I have revived some fruit trees that were very old and no longer producing by fall fertilizing; I got almost $700 worth of organic pears and even more than this in apples last year through fall fertilizing).
I also heard (and studied it last year in my own garden) that potatoes grow between the seed potato and the surface. If you bury them deep you will increase yields as there is more space for them to grow above the seed potato. But if you plant them shallow, they have a very narrow area to make potatoes in, significantly reducing production. This means in container gardening you need to put them at the very bottom of a 1'-6" (0.45 meters) tall container to get a full yield. I tried this method last year and doubled my production. I was putting them very close to the surface before last year.
Also, potatoes need cool roots and won't produce anything at all if their roots are too hot in the container during the summer. Afternoon/evening shade is a must in Southern US zones or other hot environments. Or you could insulate or shade the container.
I live in Southern California Zone 10A and grow potatoes year-round in bags and containers, anywhere from 5 to 15 gallons size. I have found what works well for me is to put about 4-6 inches of good soil in the container, lay a few seed potatoes on top so the slips are pointed up, about 12 inches apart, then cover them with about 4-6 inches of soil, and water moderately or they will rot. These potatoes will only produce new tubers in the soil about 6-12 inches above the original seed potatoes, so when the plants are about a foot above the soil, if I have any new add seed potatoes and the container has enough room, when I add more soil I may consider adding a few more seed potatoes that will produce "baby potatoes" above the older tubers, then cover them with another 6 inches of soil that will also bury more of the new growth of the first seed potatoes. Doing this stimulates more growth, and I may even add even more soil as the plants get taller depending on the depth of the container. I don't always add the second layer of seed potatoes, but doing this produces a few larger potatoes below (Baked Potatoes!) and a lot of smaller potatoes above them, and they are all excellent eating. I am growing Russet, Golden, and Red potatoes in containers, but I think they are all determinant varieties since they are all started from potatoes purchased in grocery stores, and each plant only produces tubers in the area near the seed potato, but do not continue to produce tubers as the plants get taller no matter how much more soil is added. I am still learning as I go, such as "location, location, location!" is making a noticeable difference on how successful my efforts are, and I would like to find an indeterminant variety potato that will grow well in Zone 10A.
06 May 23 Benjamin Chapman (Australia - temperate climate)
I have been told that the terms I used (specific and non-specific) could be wrong. Someone else has said the terms are "determinate" and "non-determinate".
08 May 23 Celeste Archer (Canada - Zone 5a Temperate Warm Summer climate)
I'm not certain if the initial question is using the correct terminology or not... there are so many different ways to categorize things. If it is determinate verses indeterminate -- then it is like tomatoes -- the indeterminate are like a vine, and continue to grow - which means they CAN BE towered ( but don't have to be) and they will continue to put out "layers" of tubers as you hill up. However, indeterminate potatoes can be grown as determinate.... you DON'T HAVE TO tower or hill up -- so long as you plant the seed potato deep enough. You can get more potatoes per square foot of real estate out of the indeterminate type of potato, but it does take longer. So you need to think about - time verses space verses growing methods.
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This planting guide is a general reference intended for home gardeners. We recommend that you take into account your local conditions in making planting decisions. GardenGrow is not a farming or commercial advisory service. For specific advice, please contact your local plant suppliers, gardening groups, or agricultural department.
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