Potato seed choice and preparation, planter setting, and creating the best seed bed all drive better plant emergence.
Steven B. Johnson with the University of Maine told the 2020 Ontario Potato Conference and Trade Show held in Guelph March 5, that managing seed is critical to getting even emergence.
Why it matters: Inefficient emergence can set farmers up for an inefficient growing season.
“First of all, you have to love your seed. That is a very critical thing. You have to treat it well and seed is something I put a lot of focus on,” says Johnson.
Farmers need to understand the variety they are working with. Especially when working with, especially when working with a variety new to the region.
“It’s good to get a growing profile from a breeder or an area expert to see how it produces and performs.”
It’s also important that farmers know the soils they are working with, weather patterns and past issues with disease to understand how to best grow their potatoes.
“Physiological age is one of the big key things about getting a crop to perform properly,” says Johnson.
Seed age affects the way it produces sprouts.
Middle-aged seed is the best for profitable production, a more desirable age for most conditions. It has virtually all the sprouts breaking at the same time.
“You get more stems, you get more tubers and you have an opportunity to size them up,” said Johnson.
Younger seed is known to make only one sprout, producing a two to three-kilogram potato, which is not desired by processors. If too young, the seed is dormant and produces zero sprouts.
Older seed has a shorter season and produces weak stems. When aged too much, it is known as no-top, producing only a tiny tuber, which doesn’t emerge.
Upon emergence, it’s important growers look at stem count and not stand count.
“If I’m planting 15,000 plants an acre, I want three to five times that many stems. I need all the plants to come up, but I need the stem numbers to make the tubers.”
For better emergence, the seed needs to be warm. Planting cold seed into cold ground is not ideal.
If the seed is not properly warmed, it can create condensation on the tubers generating bacteria sprout rot.
“The difference between the air and the tuber temperature is critical. The bigger the difference, the lower the humidity. You really need to try and avoid the condensation.”
Seed cutting is critical to optimizing planting.
“Seed comes in all sorts of shapes and sizes. The tighter the range of seed, not from really small to really big, the more efficient and better your seed cutters will be.”
If the seed cutters are more consistent, it will plant more consistently and place the seed where the grower wants it.
It’s best to have two-thirds to three-quarters of seed potatoes in a fairly narrow range. Planters move faster today and the faster the planters move, the tighter the seed range must be.
It’s best to consistently calibrate the seed cover to have the planter work more efficiently.
As well, planters perform better with uniform seed — seed that is blocky, clean, with evenly distributed seed treatment and consistent cuts.
“When the distribution is poor, (potatoes) fall off, knock two or three down below and misses occur. Too many of the tiny ones get planted doubles or triples. That’s not what we’re looking for,” said Johnson.
Other factors such as soil temperature, fertilizer, planting depth and speed of planter are also important to consider for proper emergence.