Growing better plants in the sand – 2020 soil trials

After 4 years and thousands of dollars lost, we are looking for a better way to grow plants in our sandy soil. The soil trials began in the spring of 2020.

The soil trials are based on the assumption that we can improve sandy soil by adding liquefied clay. A company in Sweden is working on improving the deserts of the world by adding liquefied nano-clay. Their data looks impressive and they are slowing trialing their methods around the globe. Maybe they will help us out one day, but for now, we are trying it on a smaller scale.

We have 6 study beds. Each bed is approximately 3’x7′ and is laid out in a sunny section at the edge of our prairie in the sand plains of Minnesota. Why the edge of the prairie?

  • The area grows very little plant material – it is dry and windswept
  • We are planting “fast growing” native prairie forbs in the trial and they will be encouraged to spread into the rest of the prairie
  • The area is around 100 feet from our beehives and the selected plants are “bee faves.” Since bees travel over a large distance, this spacing gives us a central location to assess bee activity.

This is how the beds were set out:

  1. Compost – spread 3 inches above original soil and sprayed with liquefied clay
  2. Topsoil – spread 3 inches above original soil and sprayed with liquefied clay
  3. Original sandy soil – sprayed with liquefied clay
  4. Compost – spread 3 inches above original soil
  5. Topsoil – spread 3 inches above original soil
  6. Original sandy soil

All beds were raked flat and sprinkled with an equal volume of a prepared native flower seed mix. The majority of the mix was anise hyssop and prairie coreopsis. We also included harebell, flowering spurge, and prairie blue sage.

We have planted hundreds of native seeds in our 12 acre prairie over the years. We have a wide variety of plants growing (approximately 30 to 40 species are actively growing.) Many more are still waiting to germinate? We created this particular seed mix to add variety to the existing prairie, to grow quickly (anise hyssop and coreopsis) and to serve as a pollinator check point.

Check out this article for more ways to improve sandy soil.

Here’s a reminder of how the beds looked at the beginning of the trial – March 2020

Basically – just empty soil. The ground was still frozen when we put down the soil and seeds. The seeds had at least 1.5-2 months of freezing temperatures and spring wetness.

Update #1: June 20, 2020

Compost + Clay
Top Soil + Clay
Sand + Clay
Compost
Top Soil
Sand

At the beginning of summer, it’s not looking very promising. But…this is not our first rodeo with native plants.

In the larger prairie, it took 3 years before we saw anise hyssop. And we are still waiting for prairie coreopsis (4% of our original seed mix!)

Just because it can bloom in its first year doesn’t mean it will. Plants have their own timeline.

The sand plots are definitely going to have more grass and yarrow competition because the ground wasn’t smothered by 4 inches of soil. Time will tell…

Update #2:

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