This was our first year attempting to grow potatoes. Before planting I did quite a bit of research, and followed some tips that sounded reasonable to me. The results, however, were not what I had hoped. A while back I posted about my results on Earthineer and between the responses I received there, and some additional research, I think that next year's potato crop should do better.
We planted three varieties of potatoes this year: Yukon Gold, Pontiac (red), and Kennebec (white). All 3 were planted on April 20th. We did not do a soil test, which is something I realize we should have done prior to planting. The ground appeared to be very rich. It had been dormant for years, and actually was very overgrown until I cleared it this past fall. I expected the potatoes to do well in the dark, crumbly soil, so we did not add any compost or other ammendments. Before planting I tilled the entire area, then created a trench 6 inches deep for planting the potatoes. We planted a row of each type, with the rows spaced about 24 inches apart. We planned to hoe them and hill up some dirt around the plants when they reached 12 inches tall, but we didn't do that until a bit later than we had planned, when some were probably approaching 18 inches. We hoed them again in June and again added to the dirt surrounding the plants. We started watering the plants, at first weekly, and then more often, once we stopped getting rain. June was extremely dry, with less than half an inch of total rainfall.
The Yukon Gold had grown very tall, most were probably 24 inches. They had few leaves on the lower portion of the stem, which made me think we had a problem. The other varieties looked a little better, but still weren't as bushy as I had expected. Once the majority of the Yukon Gold and Kennebec plants looked dead we decided to go ahead and harvest those. This was at the beginning of July, which was much earlier in the season that I expected to be harvesting potatoes. I suspect that the problem was lack of water.
Yields of both Yukon Gold and Kennebec potatoes were very disappointing. We did get a handful of decent sized Yukon Gold, but most were approximately golf ball sized. The Kennebecs were generally not as big, which was expected since they have a longer period to maturity than the Yukon Gold. There were more of the Kennebecs, though, and I do believe that the yield would have been decent had they been allowed to grow until later in the season. With dead plants, though, I knew there was no chance of them growing any larger.
During the harvesting of the first two types I noticed that the stems of many of the plants were slimy below ground level. Approximately 12 inches of most plants were underground and it was the bottom 6 inches that were slimy. The feedback that I received from the helpful people on Earthineer has convinced me that the sliminess was likely due to the way in which we watered the plants prior to harvest. Potatoes prefer a good weekly soaking as opposed to several lesser waterings. We made the mistake of increasing the frequency of watering as the drought conditions worsened and as the plants looked less and less healthy. This is one thing we will me very mindful of next year.
I had planned to harvest the Pontiacs shortly after harvesting the other varieties, but after discussing it with my Dad I decided to wait. His reasoning was that even though the potatoes were no longer growing, they would store better in the ground than if we dug them. If we had a good way to store potatoes, this might not have been the case, but since we would have just kept them in the pantry, I thought his logic made sense.
When I finally dug the Pontiacs I was somewhat surprised. The yield still wasn't great, but it was much better than the yield of the other two varieties. I had not thought to weigh the other types, but did the Pontiacs. The total yield was just over 5 lbs, which isn't very good considering we planted 5 lbs of seed. We had a few potatoes of decent size, with the largest being maybe 3 inches in diameter.
In addition to changes to our watering methods I also have a couple of additional changes in mind for next year's crop. The first change is to not plant them in a trench like this past year. In better soil that approach may have worked well, but what I found is that in our situation the soil on either side of the trench was so hard that it likely limited the ability of the roots of the plant to spread and certainly limited the space for the potatoes to form. When we planted it appeared that the soil was nice and crumbly, but after a month with almost no rain we found the soil to be very hard.
The other change I have planned is the timing of when we begin hilling dirt up around the plants. We had intended to do this earlier in the process, but for some reason didn't get to it until the plants were quite tall. I suspect that this had a significant impact on the yield, so is something I want to focus on next year.
We may also try to plant the potatoes earlier in the season next year. Based on when others, who had better yields, planted this year we were probably 2-3 weeks late. Maybe we can aim for planting during the first week or two of April this year. I've been told that Easter Weekend is the traditional time for planting potatoes in our area. This year Easter was on April 8th, which was 12 days before we planted our potatoes. In 2013 Easter will be on March 31st.
I'm looking forward to attempting to grow potatoes again next year. I'm confident that our results will be better than this year's. Gardening is definitely a learning process for us, so if we can improve results each year I will be very satisfied.