Planting Potatoes at Upriver

We try to plant our first potatoes on March 17th every year. I’m not sure if this is the ideal time, but there’s something about the Irish, potatoes, and the fact that it’s Saint Patrick’s Day, it just feels right. 

People grow potatoes all over the world, and since they were originally domesticated up high in the equatorial Andes mountains 7,000-10,000 years ago, I suspect there are different planting dates for different places. So there’s nothing special about Saint Patrick’s day that coincides  with a traditional potato planting date, to my knowledge. Once potatoes made their way to Europe via the Spanish, later in the 16th Century, they became so popular that these days many people don’t even know that their original place of origin is actually the Americas. 

Fingerling variety "Amarosa"

At Upriver Organics we grow 4-5 varieties each year. We typically grow a purple flesh and skin type, a red skin type, red flesh type, a yellow Yukon Gold type, a red skin/white flesh type and sometimes some fingerlings. With all this diversity we are just scratching the surface on potatoes. There are over 3000 varieties of potatoes solely from South America, and many of them are very different from what you can find in the grocery store. They come in all different shapes, sizes, colors and many of them are far more complex and flavorful. In fact, in the US most farmers grow more Russet potatoes. These are great potatoes for French Fries, tater tots, etc.

The Russet potato was developed in the US in the late 1800’s by the plant breeder legend Luther Burbank. He introduced it with better blight resistance (a major potato disease), and with a tough exterior that resists pests and blemishes (that rough skin is where it got its name).

Now, back to planting… 

Preparation for our St. Patty’s Day planting starts a few weeks prior, in late February when we get our seed potatoes delivered. Our potato seed usually comes from a Certified Disease Free supplier in Idaho or Colorado. They grow the potatoes where it’s cold and dry, which helps to reduce tuber-borne diseases. Their cold winters can break disease cycles that we can’t here with our mild winters. We say potato seed, but they’re just potatoes that we use as our seed stock. Potatoes also produce true seed from a small tomato looking fruit, but it’s genetically variable and not a genetic clone of the type we want.  So instead of true seed, we use root pieces for seed instead, which ensure true-to-type potatoes. 

We will begin to harvest these first potatoes around July 4th. 

While we plant our first potatoes in March, we also have a 2nd planting in June. This second planting gives us potatoes that we will harvest in September or October, and store until April of the next year. 

Chitting

When we receive our potatoes, we put half of them in the cooler for the June planting, and the other half into the greenhouse for “chitting”.

Chitting is the act of pre-sprouting potatoes before planting in the field. There are several ways people do this, but our method is as follows: 

We bring the potatoes into the greenhouse and lay them out on tables. Then, we cut any large pieces down so that our average seed piece is ~2oz, and each piece has at least one eye (sprouting point). We then leave them here until we plant. This allows the potatoes to wake up,  open their eyes and start to sprout. By giving them light, they don’t sprout too fast, like they do sometimes in the home cupboard. Their sprouts are usually less than a ¼ inch when we plant them, so they won't break off when handled. 

Planting field prep

We try to plant our potatoes into a fairly weed-free spot, which is hard to create early in the year. To help with this problem, we start planning our planting location for potatoes the year before. The spot where we plant our potatoes is always a spot where we grew Sudan grass as a cover crop the summer before. Growing Sudan grass is wonderfully easy to grow, grows vigorously, and shades out all the weeds. It also can’t deal with frost at all, so it dies off entirely in the winter. The Sudan grass plants are usually flattened to the ground by snow and rain, and the soil is left very aerated by all the dead Sudan grass roots. We mow and plow this in during March, whenever we get our first dry spell. With our sandy soils, we are able to work our soils with relatively short dry weather windows, but some soils won’t permit this. We amend the beds with some additional chicken manure, and sometimes compost. We then till and shape beds for the potatoes. This weekend the weather was perfect for this in our fields.   

The winter killed and mowed Sudan grass stubble

Final bed shaping March 16th 2024

We plant our potatoes on these beds two rows 18” apart and 8” between root pieces. We usually use a tool handle to pre-punch a small hole in the ground 4” deep to place the root piece there. 

Watering

The potatoes are not usually watered for the first month or more that they are in the ground. Often in late April we will start watering, if the rains stop. This watering is done with drip irrigation, and we will water 1-2 times a week depending on the weather.

To hill or not to hill 

We used to hill our potatoes, and there are plenty of good reasons to do so, but for our system. we found it unnecessary. We may get a few less potatoes, but for this early planting, it matters less. Hilling helps with weed suppression, and it does a good job. It also can disrupt the pest cycle of the flea beetles that love to live on potatoes. The adult flea beetles can put a lot of small holes in the potato leaves, but that’s usually of little concern. The problem is that they lay their eggs in the soil, and the larvae emerge to feed on the tubers, leaving trails all over the surface of the potatoes. Weekly hilling can interrupt this, but heavy mulching is also helpful in disturbing the flea beetles laying eggs. 

Row cover

We sometimes cover our potatoes with a row cover to accelerate their growth and protect them from a late frost, but you can also just let them grow at their own pace. They will usually start to emerge in April, and assuming it doesn’t dip below 30 or so, they can tolerate a light frost. Even if they should get frosted, the potatoes have lots of stored energy in their roots and they will send another shoot out. 

I’ll cover harvest and storage in another post later in the season.