In Minnesota, "prepping the soil" is less about digging and more about timing. Because we have heavy clay in many areas and a very short window between "frozen" and "planting time," how you handle your dirt determines how well your plants will breathe.
Here is your step-by-step guide to preparing Minnesota soil for spring and keeping it healthy all season long.
Step 1: The "Squeeze Test"
The Golden Rule: Never work Minnesota soil while it is wet. If you dig or till wet clay, it collapses the air pockets, turning your garden into a "brick" once it dries. Roots can't grow through bricks.
- The Test: Pick up a handful of soil and squeeze it into a ball.
- The Result: If it stays in a tight, sticky ball, it’s too wet. Wait a few days. If it crumbles easily when you poke it with your thumb, it’s ready to prep.
Step 2: Get a "U of M" Soil Test
For about $20, the University of Minnesota Soil Testing Lab will tell you exactly what is in your dirt. This prevents you from wasting money on fertilizer you don't need.
What it tells you: Your pH (acidity), organic matter levels, and phosphorus/potassium needs.
Why it matters: Many Minnesota soils are naturally high in phosphorus. Adding more can actually harm our local lakes and rivers.
Step 3: Amend with Organic Matter
Minnesota soil usually falls into two categories: Heavy Clay (in the Twin Cities and suburbs) or Sandy (in Central Minnesota and along the Anoka Sand Plain). Fortunately, the fix for both is the same: compost.
- For New Beds: Spread 2–3 inches of high-quality compost or aged manure over the top.
- How to Mix: Use a garden fork to gently turn it in to the top 6–8 inches of soil. You don't need a heavy tiller. "Low-till" gardening keeps the beneficial earthworm tunnels intact.
- The "No-Sand" Rule: If you have heavy clay, never add sand to try and "loosen" it. Clay + Sand = Concrete. Stick to organic compost or peat moss.
Step 4: Feed the Microbes
Think of your soil as a living organism.
- Top-Dressing: Even if you aren't digging a new bed, add a 1-inch layer of compost to your existing perennials every spring.
- Mulching: Once you plant, add 2 inches of wood mulch or shredded leaves. This prevents our hot July sun from baking the soil hard and keeps the moisture where the roots can reach it.
Step 5: Consult the Experts
If you find yourself with a thorny problem or issue with your garden, it's a great idea to ask for help. The staff at Untiedt's Garden Centers is always ready to talk about ways to solve your gardening problems.
Untiedt's also carries a wide variety of soil, fertilizer, and other supplies that will help keep your garden growing vigorously.
Your Minnesota Garden Soil Spring Checklist
- Wait for the soil to dry (do the "Squeeze Test").
- Clear away last year's dead debris and check for pests.
- Test your soil with the U of M Testing Lab.
- Layer 2 inches of compost.
- Loosen gently with a garden fork.
