Perennial Garden Bed Preparation by Evelyn Fielding of Beier's Greenhouse

Whether you're prepping a brand new perennial bed or working with an established perennial garden, ensuring the health of the soil ensures your plants live and bloom for many years. Begin by getting the soil tested so you know what to add. Then, add organic matter such as compost or composted animal manure every year. Finally, keep in mind that mulches change the soil's nutrition levels and pH, so you'll need to pay attention to what's happening in the garden. Water thoroughly after adding amendments, and you're ready to plant!

Soil Testing for Perennial Gardens

Most perennials prefer to live in slightly acid soil at a pH of 6.5. Adding amendments to the soil changes its nutritional value and pH, usually in the right direction, but you can't be sure until you've tested the pH and main nutrient levels.

It's incredibly easy (and cheap) to get a rough idea of your soil's composition. Go to Ace Hardware and ask where they keep the soil testing kits. Follow the directions on the package carefully and you'll have readings within about 10 minutes. Alternatively, call the Southwest Conservation District offices at (218) 326-0017 to get a complete soil test performed in the University of Minnesota labs, and you'll only need to wait a week or two for results.

Check the pH and nutrient levels of your soil each spring. Check it again about two weeks after adding major amendments.

Adding Compost

All soils benefit from compost. If you're working with a new perennial bed, add up to six inches of good compost and till it into the top twelve inches of soil. If you have established plants or aren't lucky enough to know someone with a tiller, spread three inches of good compost around the plants and work it in with shovels and garden forks, trying not to dig up the plants as you do so. It's also OK to just use compost as mulch, leaving it on top of the soil.

If you don't make your own homemade compost or you need a lot, go to the composting site in Grand Rapids just off River Road as you're heading south (on the river side of the road). Bring a trailer or pickup, a good friend, a couple of shovels and a pitchfork.

Adding Manure

Composted manure is another excellent soil amendment. If you need a little, buy a few bags from Beier's. If you need a lot, talk to your neighborhood horse, dairy, or rabbit farmer.

Just be sure that manure direct from the farmer is thoroughly composted—in the case of horses, three years is minimal and five years is ideal. Cow manure needs to compost for a minimum of five years. Rabbit manure doesn't need to compost at all—just put the pellets right into the garden after they leave the animal.

Other Amendments

Sandy soils can be improved through compost or animal manure, or by adding peat moss. Peat moss is good in small amounts and can be purchased by the bag at Beier's Greenhouse. Sphagnum peat moss is quite acidic, though, so watch the pH levels of the soil if you're adding a lot.

We don't have too many clay soils around Itasca County, but you might be unlucky in that regard. Add coarse sand to clay soils and mix thoroughly. This loosens the soil and allows the clay particles to clump together properly, increasing drainage and reducing lumpiness. You can get coarse sand (also called sharp sand by contractors) by calling any of the concrete manufacturers in the area.

Here's an interesting bit of knowledge: If you use straw, shredded bark, wood chips, or sawdust as mulch, you need to add nitrogen fertilizer at the same time. The microbes that decompose these materials need nitrogen, so they take it right out of the soil causing a temporary nitrogen deficiency. Eventually the process balances out but your plants may suffer in the meantime. Add fertilizer, or add compost or animal manure and top with fresh mulch.

Finally: Water, Water, Water

The last step to preparing a perennial bed is to water thoroughly several times before adding new plants. This settles the air pockets out of the soil and gets the nutrients going. If you've added a synthetic nitrogen fertilizer to the area, watering distributes the nitrogen and keeps your plants from getting burned.

Wrap Up the Task

Prepping a perennial bed, whether brand new or established, is an important spring routine. Get your soil tested for pH and main nutrients so you know what needs to be added. Use compost or animal manure each year, either working it into the soil or as mulch. Keep in mind that certain popular mulches such as shredded bark and wood chips may cause temporary nitrogen deficiency in the soil, and apply fresh layers every year or two along with a good nitrogen source.

The bed is ready—time to transplant some of those long-lived and beautiful perennials into their new home. Take good care of your perennial garden and it will reward you with decades of life and color.