It’s the time of year to start preparing your garden, whether you’re planting flowers or looking forward to a bountiful vegetable harvest. Many gardeners don’t like the preparation part of gardening. I can understand that – we’d all rather skip directly to the part where we see green shoots coming up from the ground and becoming full-grown plants.
But once you have a full appreciation of this beautiful peninsula where we live, the subject of soil gets much more interesting. For example, did you know that there are 75 different soil types and sub-types identified in Door County? We have everything from Alpena gravelly sandy loam to Markey muck to Summerville loam. All of our soil comes from glacial or lake material, because between 1.8 million years ago and 10,000 years ago, glacial sheets advanced and retreated several times over our section of the Midwest – sheets that were sometimes two miles thick! Green Bay’s glacial events were responsible for our peninsula’s unique features: the carving out of Green Bay, Lake Michigan, the Niagara escarpment, and forming drumlins (those mounds in the shape of “smooth inverted spoons” you see throughout the county, especially in Liberty Grove, where the glacial deposits are the oldest).
Because of our rocky underlay–that beautiful escarpment–much of our soil is very shallow, especially in Northern Door. In fact, 22% of the soil in the entire county is less than 18” in depth, and another 17% is just 18 to 36 inches in depth. When you think about the challenges involved in Door County gardening, it’s amazing we can grow anything at all!
Door County soil sometimes needs our help to give plants their best chance, which often means amending the soil with minerals or other substances. Yes, there are plenty of minerals in Door County – calcite, dolomite, fluorite, gypsum, hydrocarbons, marcasite, pyrite, and quartz – but they’re all in the rock formations and in quarry digs, not directly in the soil.
Soil studies often talk about our cherries and apples, but the principles of soil fertility also apply to your own backyard plots and flowerbeds. Having fertile soil depends on the soil’s capacity to hold water, its workability, and its natural chemical composition. If you’ve been a gardener for a while, you already know the texture of your soil just by rubbing it between your thumb and fingers. With experience, you’ll become an even better judge. For instance, a coarse sandy soil won’t retain moisture as long as a loam soil or clay loam. The seven types of soils in Door County are classified as clay, silt, very fine sand, fine sand, medium sand, coarse sand, and fine gravel (although “Door County potatoes” have to classify as No. 8!).
Here are some quick tips about adding amendments to your soil. You can always come into Jerry’s Flowers with a small soil sample, and we can help you choose just the right additions. One of our favorite suppliers is Dr. Earth. Their additives and fertilizers have been consistently high quality. Pre-mixed formulas such as this don’t require any guesswork on the amount of minerals or other supplements. Dr. Earth is all organic, tailored to the type of vegetable or flowers you’re planting, and even contain beneficial soil microbes. Here’s a quick checklist of soil amendments dos and don’ts:
• Amendments are materials you mix into the soil; mulches go on top of the soil.
• Soil amendments are meant to aerate soil, give it better water-holding power, and improve nutrition. For instance, a clay-like soil is very compact and needs additives that loosen the soil, leaving room for roots to branch out and grow.
• Wood products are not the best idea for amendments or soil; they can tie up the nitrogen in soil, and when used on top of soil, they are a big attraction to pests like termites.
• Soil amendments can be organic or inorganic. Organic amendments include grass clippings, straw, compost, manure, biosolids, and sphagnum peat. Inorganic amendments include vermiculite, perlite, pea gravel and sand. We prefer organic amendments that increase contain plant nutrients and also act as an energy source for bacteria, fungi, and earthworms that live in the soil.
• Some forms of compost can be high in salts. Raspberry, strawberry, bean, carrot, onion, viburnum and many other landscape plants are salt sensitive.
Above all, ask us! We’ll be glad to evaluate your soil and the challenges you’re having, and then recommend the best solution for your garden.