We have always battled potato scab. Some years I have had better luck than others. I read online that if you grow your potatoes from seed, rather than last year’s tuber, they will not pass on diseases. In addition, if the seed is grown in your own garden, it will be more adapted to your climate.
Last year my potatoes had blossoms and set seed. I decided to try an experiment with them. In February I planted the tiny seeds, using many more than I wanted because I did not know what their germination rate would be. Of course they all sprouted.
Because it was so early in the year and because they were grown by natural light in the windowsill, they got very leggy. In late March I put some of the seedlings in the greenhouse and some of them in the garden. The plan was to grow them in the same way one would tomatoes, with successive transplanting to give more root structure. The bigger the pot I put them in, the bigger the seedlings grew. The greenhouse plants definitely grew larger. But strong plants grew in both places. I chose the best to plant in the bed, burying the majority of the plant in the soil.
By mid-May they were very healthy and well ahead of the tubers that had been planted in the same bed in late April when the soil temperature had reached 50º.
The tuber plants did surpass the size of the seed grown plants both in size and in production. I had used sulfur in the soil before planting. I believe the scab was low on both types of plants because of this.
I had read that the potatoes would be small, so I intended to use them as seed potato for next year. I was pleasantly surprised at how large some of the potatoes got.
A 7” tall seed grown plant had only 2 ounces of tubers. There were 7 and the largest were about 2 inches long. However a 15 inch tall plant had 1 lb 10 oz of tubers. There were 18 and the largest were about 4 inches long, 5 inches in circumference. Both had a few scabs, but not too bad.
I feel this experiment was successful. One of the seed grown plants has blossoms on it (see the first photo above.) I am hoping to get a second-generation seed that will be even more adapted to our garden. We will continue to keep the scab at bay with sulfur and to acidify the soil and seaweed to fortify the plants.