This is my first year trying to grow potatoes. Since our soil is clay I tried the method of hilling them in straw - but I had no success. Can someone tell me what I did wrong before I never try this method again? Below is what I did:
The potatoes were planted a month late due to insane amounts of rain this spring, couldn’t get into the garden. They were already sprouted several inches long before planting. I buried the tuber just under the soil and left the sprout above ground, then mounded with lots of straw and did this 3-4x over the summer until the plant was almost entirely buried.
I thought potatoes grew up the stem? Zero of my plants grew any potatoes up the stem, basically all of that straw was useless. I found maybe 2 baby potatoes per plant right at the soil surface, the only place that had any potatoes growing.
I had a mix of varieties, the German butterball performed the best but that could either be the variety or because this one variety had the smallest sprouts before planting (some of the others had gotten pretty long - most of these never grew above the straw and died).
Sometimes potatoes will form a little bit higher up on the stem - covering them with straw helps keep them from turning green. Fingerlings can also form on a stolen from another tuber - chaining two or three from the original one, but they don’t grow up
Soggy soil isn’t good for potatoes, that may have been your problem. Or planting too late. Or pests could have destroyed the tubers underground
Potatoes that already have long sprouts are not the best for planting. Start with dormant potatoes from reputable source. Try to get them a month before planting time(or earlier and keep refrigerated) and cheat them in the tray on a sunny window. Spray with water once a day, or keep them in clear covered veggie boxes with holes for ventilation(the ones you buy produce in in winter) . Place them the way the best eye is up. They will start forming SHORT sprouts, with leaves and roots. They can stay that way pretty long if they have enough sun. When you can get to the garden, loose soil at least 10 inches deep, mix in some fertilizer with good number for super phosphate in top 3 inches of loose soil, place potatoes on top of loose soil, cover with 4 inches of compost mix and some straw. As soon as you see leaves above the straw - add more straw. Make sure your straw is moist, but not soaking wet. I found that overwintered straw works best. If you have source of compost you can add a thin layer of compost on top of the layer of straw. It helps with nutrients and to keep straw moist.
For growing up the steam. No, they usually do not grow up the steam, may be just a little bit, but not to the top. . First set of potatoes develops right above mother potato and bellow the steam, But, if your potatoes have enough time and nice conditions, they start to produce runners, that go up, and you get secondary crop on those runners. So far I found that Red Pontiac does it the best. I can pick 2-3 times from the same plant if I just dig down with my hand, with last tubers just below straw. Commercially grown potatoes usually don’t do runners - runners tend to go up and potatoes on them may get green because of the sun exposure, so farmers avoid them. If you manage to get you runners, make sure forming potatoes covered with straw very well. Good luck!
I agree pretty much with what’s been said, but let me add this. Potatoes do not need to form in dirt BUT the stem from which they grow needs to be in contact with dirt, or compost, or some growing media in order to send out shoots to form potatoes.
I saw this poor fellow on youtube who constructed a set of open boxes that you could stack one upon another - lots of work. And as the potato plant grew he added more straw and another box if needed. By the end of summer the boxes were stacked almost as tall as he was. As he began to harvest, pulling each box off, there were no potatoes in any of them except a few that were in the very bottom where soil or compost or decomposed straw actually came in contact with the stem.
Thank you for the advice. I am surprised because I had read online that potatoes grow upwards up the stem which is why you have to continuously hill them… as opposed to sweet potatoes, which grow downwards so you only have to plant them and that’s it.
So if the potatoes will only grow in dirt, why is there this popular hilling with straw method? What’s the purpose of hilling with dirt, that would work better than hilling with my straw? If the potatoes grow underground then why continuous hill?
Because they can poke up out of the ground. Some russets, especially, will grow at an angle so several inches are exposed if not well covered
Another reason - to hold in the moisture that potatoes need to grow well. When I have a good thick layer of straw down, I can dig my fingers into it and touch the damp earth even when there’s been no water for some time. Straw is better for this than earth
No, they grow not only in dirt - as I said, they make long underground shouts - I call them runners. They will go up, and they will produce potatoes in the straw. At least, Red Pontiac does. I think most usage of straw is for cages, where runners can’t go much to the side, but they can go up. As you add more and more straw the new runners that appears from the same spots where new potatoes forming find the place to go - they go up. In ideal world, if you plant in ideal conditions in ideal loose fertile dirt with no competition for the roots in any direction, they will grow runners horizontally. But in real life, where there are obstructions, compacted soil, other plants sending hormones out that the spot is occupied - they look for better condition. And better in this case is where loose material, moisture and some nutrients are - up your straw.
Lots of good advise so far and I also agree with most of it. My experience is as your soil gets better and looser with more organic matter the potato harvest will be better. As the straw you mulched with rots that will help your soil so all is not lost. I plant mine just under the soil so I don’t have to dig so far down (you can plant them deeper). As others have said they do spread outward though that depends on the variety, some stay by the mother spud, some travel. I mulch them well with hay (my preference since it has more nutrients than straw), maybe 6", enough to cover well. But many mulch materials will work. When the plants are growing well I put on more hay, snugging it up under the plants against the stems. Some folks do with this dirt not mulch. It does the same thing, gives the new potatoes a place to grow easily and keeps them out of the sun.
It helps to check them later in the season to make sure all tubers are well covered with dirt or mulch. I find the mature plant stems tend to fall outward, leaving the center open and tubers exposed. Sun greened tubers are throw-aways which is always irritating when I’ve let that happen.
I’ve also seen many articles over the years about growing potatoes in bins of some sort so I can understand your confusion! But as fruitnut said, the tops do need the sun but the tubers definitely want to stay covered. There are a lot of different ways to do that, successfully. But one learns with experience (and the learning never ends!). I’ve no doubt you’ll be growing some good spuds in future years.
Another important factor in tuber formation is temperature. Once I had grown potatoes in very large landscape pots that were black. Whereas that is an advantage coming out of winter, I planted these as a second crop and they went through our July and August and yielded no tubers. After the solstice the sun shines on the side of those pots and likely heated them too much. Then I came across info that tubers don’t form if soil/straw/whatever they are growing in, is greater than 80 deg F.
So Janet, if you got them out late and the straw was insufficient to capture ground coolness, that might explain your result. Note how much straw @ltilton used.
Whoops. Meant to mention that could have been the youtube guys problem I mentioned above too. Air temp in those kinds of boxes in some areas at some times in the summer is pretty warm.