I dug another bed's worth of potatoes this weekend. At this point in the season, the bed is starting to look a bit ragged.
The overall bed-size is 2x12' and I harvested over 22 lbs of potatoes, 105 days after planting (on 6/11).
11 Magic Molly- 7.2 lbs
7 yellow fingerlings from Whole Foods- 3.0 lbs
3 Borra Valley- 5.8 lbs
7 yellow fingerlings from Klondike- 0.8 lbs
7 Purple Majesty- ~6lbs (last weekend)
I also made a Youtube video of me digging them (sorry- it is a bit shakey). The Bora Valley plant in the video totaled more than 3 pounds. I got to thinking about what could have caused such a good yield and had a couple thoughts.
1.) I made the bed this spring and the top layer is from some old potted plants that I mixed in with the native soil. So, maybe whatever I dumped in that area had more/less fertility or better/worse drainage.
2.) I remember hand watering some this summer and there was one time that I just left the hose on the ground and got distracted by something. I over-watered that time, coming back maybe 5 minutes later. Thinking about it, I think the hose was about where the good yield came.
I think #2 is the more likely option, as I tried to mix everything in. Maybe I should try weekly flood irrigation when there is no rain in July/August. If I managed to replicate the results for all 35 plants, I would have had over 100lbs from that bed! That would be over 4 lbs per sq ft.
It occurred to me that maybe the seed potato for that plant was bigger than the others, but I checked back and had a photo of when I planted. The red circle is that large plant from the video.