Small potatoes

It didn't occur to us until recently that, when we planted potatoes for the first time this spring, there was one thing we didn't pay enough attention to: how to know when it was time to harvest them. After thriving throughout the spring and summer, the vines started to wilt and die back, and we weren't sure whether that meant it was time to harvest the potatoes or not. Eventually I checked on it and found that potatoes grown in this way are supposed to be ready to eat after 12 to 20 weeks — which meant we were anywhere from one to three months late gathering them in.

So, yesterday, Brian decided to investigate. He pulled one of the buckets out of the garden and started rummaging through it, searching for spuds.

The first one he found was a tiny little fingerling — maybe half the size of the ones we'd bought as seed potatoes to start with — and he thought, "Gee, I hope the rest are bigger than that." But he kept digging, and eventually he found about a dozen more...all smaller than that first one. The entire harvest from that bucket was small enough to fit into the palm of his hand. When we took them in and weighed them, they came to about an ounce total.

We haven't checked the other three buckets yet, but based on this one, it seems clear that our potato-growing experiment, to put it mildly, hasn't been a huge success. The volume of potatoes we got out of this one bucket may actually be smaller than the total volume of seed potato that went into it. If the others are similar, then the $3.71 we spent on seed potatoes will yield us around a quarter-pound of fingerlings, for a total cost of $14.84 per pound. (Sure, fingerling potatoes cost a lot more at the store than other kinds, but they're nowhere near that much.)

So, in theory, we should just eat the tiny volume of potatoes we have and write off the $3.71 we spent on the experiment as the cost of a lesson learned. (The buckets can be reused, and the compost can go back into the bin, so there weren't any other expenses.) And yet somehow, I hate to let it go at that. I can't help thinking there must be something we could do to get a decent crop of potatoes out of these buckets. Not a huge volume — maybe just a few meals' worth — but at least enough to make a profit on the endeavor. I mean, other people have apparently been able to pull this off successfully, so we know it's theoretically possible. Maybe with a few changes to our technique, we could make it work.

I checked out this YouTube video on bucket potato growing from an urban homesteader by the name of Hollis, and I can definitely see a few things he did differently from us. For instance, he added a 4-inch layer of stones for drainage to the bucket, while we only put in an inch and a half. Then, and this is probably more important, he added just enough compost to cover the stones and put the seed potatoes directly on top of them before layering on 6 inches of compost over top. We put in 4 to 6 inches of compost before adding the potatoes, and looking back on it now, it seems obvious that by doing this, we deprived them of 6 inches' worth of growing space. And obviously, the more underground space your potato vines have to grow in, the more tubers they have room to produce. (Brian confirmed that when he was rooting around in the bucket, he noticed that once he got below a certain level, there just were no more potatoes. So it seems clear that the vines grow only up, not down.)

Also, the growing medium Hollis uses is different. He said he combined equal parts topsoil, peat moss, and composted manure, rather than using all compost as we did. Now, given our druthers, we'd prefer to keep using our own compost, since it's both cheaper and more sustainable (as peat moss is technically a nonrenewable resource). However, it looks like we might not need to use pure compost; a ratio of two parts compost to one part ordinary garden soil would be closer to his mixture and might produce better results.

Third, the video recommends using two whole potatoes per bucket. We followed the advice of the folks at the Belle Mead Co-op and cut ours into pieces, then used three pieces in each bucket. However, it's possible that this actually overcrowded the vines, giving them less space for growing good tubers. Using fewer seed potatoes per bucket, could actually end up giving us a larger yield. (Hollis also used ordinary supermarket potatoes, which he sprouted by setting them in an egg carton and putting them in a sunny window. We'd prefer to grow the fancier fingerlings, since that gives us a better monetary return on our time investment, but it looks like there's no need to go to the co-op for them; we could just pick up a pound at Trader Joe's for two bucks, sprout a dozen of them, and eat the rest.)

Fourth, we set our potato buckets directly on the ground, but Hollis recommends keeping them elevated a couple of inches. His are set on top of what looks like a section of a shipping pallet. This improves the drainage and also keeps any harmful critters from crawling into the bucket from below.

Fifth, the video recommends giving all the buckets a good, thorough soaking with the hose — enough that there's water standing on top of the growing medium, which quickly drains through — right after planting. We watered ours pretty regularly, but I don't think we gave them this much water to start with, and it's possible we could have given them a better head start that way. Hollis also adds a dusting of bone meal on top to give the plants some extra phosphorus, which he says promotes root growth, and soaks them again after that. I don't know if we'd want to add this step, since it's not vegetarian-friendly, but one of the references on our gardening shelf (The Natural Garden Book) says you can boost phosphorus levels with compost, which is what we'd be using, or by raising the pH of the soil — and since our clay soil has a pretty high pH, that's another good argument for adding some of it to the mix.

Using these methods, Hollis claims he can usually get one to three pounds of potatoes out of a single five-gallon bucket. Now, the yield for fingerlings might not be as high in terms of weight, but still, if we can get even the low end of that range, our four buckets could give us four pounds of potatoes — $8 worth — for an initial investment of under a buck. (We'd use less than half of a $2 bag of potatoes for sprouting, and we'd supply the buckets, rocks, dirt, and compost ourselves.) That's definitely a result worth trying for.