The soil -- It's ALIVE!

Small plants + live soil = big rewards

By Amy McDowell

A trend has hit the perennial garden scene with a lot of force in recent years. The idea is to focus your money and energy on amending the soil and spend less money and energy on the plants.

After two decades of installing perennial gardens, author Tracy DiSabato-Aust has shown that perennials can double or triple in size during their first season—if the soil has been amended with organic matter. She convinces clients of her Ohio design and installation firm that investing in the soil is the top priority. To offset the expense of soil amendments and site preparation, she plants 4-inch (and sometimes even bare-root) perennials. Believe it or not, her tiny perennials outperform gallon-size perennials within a single season. In following years, the plants are naturally healthier and more robust because of the live soil. Photos documenting the amazing growth are included in her book, “The Well-Tended Perennial Garden”. (Timber Press, 1998)

Live soil isn’t some mushy black matter you can buy in a bag for 99 cents. Live soil has billions of bacteria, millions of fungi, plus protozoa, paramesei and nematodes—all in a single spoonful. Organic matter is the key to live soil, because it provides food for the bacteria, fungi and microbes.

Landscape Architect Terry Guen, who coordinated the design and construction of the 25-acre Millennium Park in downtown Chicago, said they purchased live soil for the park from a site in Indiana. With guidelines for soil handling and storage, they kept it healthy and alive throughout construction. They were careful not to smother or compact it by piling it too deep or driving over it with heavy equipment. As the world’s largest millennium project, planners insisted on large plants for the site, but the care they took on buying and maintaining healthy, live soil is noteworthy.

When building a new bed in your garden, add life to your soil with organic matter. Sprinkle two pounds of bone meal per 100 square feet, then add a 4-inch layer of organic matter such as compost, sphagnum peat moss or leaf humus. Till it in as deeply as the tiller will go, rake it smooth, and you are ready to plant your little ones. Then step back and watch them leap.

Planting a rain garden

Beautiful and Beneficial Rain Gardens

By Amy McDowell

Two raindrops are floating down the river, destined to become drinking water in the next city. One has been filtered clean by soaking through a rain garden. The other is carrying traces of animal waste, pesticide and fertilizer residue from turf, and petroleum products from pavement. Which one would you rather see pulled into the water treatment plant?

Rain gardens are beautiful and simple to install. They improve water quality and provide wildlife habitat.

A rain garden is a shallow bowl-shaped flowerbed planted with deep-rooted native flowers, grasses and sedges. When it rains, runoff from hard surfaces like the roof and driveway collects in the rain garden basin. The water then percolates down through the soil, and pollutants are filtered out.

Six steps to installing a rain garden

1- Choose a low spot at least 10 feet on a downward slope away from your home.

2- Test your soil’s drainage by digging a hole 16 inches deep and 8 inches wide near the center of your new garden. Pour 8 inches of water into the hole. If the water goes down at least one inch every hour, your soil is in good shape for a rain garden.

3- Lay out a garden hose to design the shape of your bed and remove the sod.

4- Loosen up the soil eight inches deep and amend it if needed. The best soil mix for a rain garden is 50-60 percent sand, 20-30 percent topsoil, and 20-30 percent compost. That 2:1:1 ratio makes the best spongy soil for root penetration and water absorption.

5- Smooth and level the soil and spread shredded mulch over the surface.

6- Install the plants, spacing them about a foot apart. This list of rain garden plants is a good place to start for a pleasing mix of colors and textures. At least one third of your plants should be grasses and sedges. 

Rain garden plant list

Blue flag iris                 Iris virginica

Bottlebrush grass         Hystrix patula

Bottlebrush sedge        Carex comosa

Broom sedge               Carex scoparia

Canada anemone         Anemone canadensis

Cardinal flower            Lobelia cardinalis

Great spike rush           Eleocharis palustris

Marsh blazing star        Liatris spicata

Marsh marigold            Caltha palustris

Monkey flower            Mimulus ringens

Nodding onion            Allium cernuum

Spiderwort                  Tradescantia ohioensis

Swamp milkweed        Asclepias incarnata

Sweet flag                   Acorus calamus

Turtlehead                  Cheylone glabra

Virgin’s bower            Clematis virginana

Wood gray sedge        Carex grisea

Buy plants in multiples so you can plant them in drifts. A list of Iowa nurseries who sell native plants is available at http://grandprairiefriends.org/nurseriesIA.html.

It's seed startin' time!

Start yer ‘maters!

By Amy McDowell

The green flag is out, garden fans. Seed starting season is upon us here in central Iowa. At the finish line we’re not greeted by the checkered flag, but the red ripe tomato. Is your adrenaline pumping? I hope so, because you are in for another gorgeous garden season and one fantastic ride.

Gather the tools you’ll need and let’s get growing. Any clean container with drainage holes in the bottom will work. Choose a quality seed starting mix and moisten it with water until it’s spongy. Fill the containers with the mix and tap it down lightly. Now sow the seeds and sprinkle a little more seed starting mix over the top. Don’t forget to label your pots.

Cover the pots with clear plastic to keep the soil moist until the seeds germinate. After they germinate, the covers can be removed for good, but you’ll have to keep a closer eye on the soil to make sure it doesn’t get too dry.

Most seeds will germinate better if you can provide bottom heat. If you can, set your pots on the top of your warm refrigerator or some other warm spot.

As soon as the seeds sprout, move the pots to a bright window or under grow lights. Bright light is important at this stage so the plants don’t get too tall and spindly. The window location may get cooler at night, so you might need to move the plants out of the window at night and back into the bright light during the day. If you use grow lights, keep the lights suspended just above the growing plants, and use a timer so the lights are on for at least 12 hours a day.

New seedlings are tender; don’t let them get too dry or keep them too wet, because they can collapse in either extreme.

One last note and then you’re off and racing. If you have the space in your garden, think about growing a little extra for the Plant A Row for the Hungry program. Because of the recession, the demand for hunger assistance has skyrocketed in recent years, and sometimes food pantries are forced to turn people away because they don’t have enough resources to assist everyone.

The DMARC Food Pantry will take garden produce, but you’ve got to drop it off weekdays between 8 a.m. and 4:30 p.m. at 3816 36^th Street in Des Moines. Maybe you can even organize a Plant A Row group in your neighborhood or church. Whatever you do, gear up and get ready for a great season.

Direct-sow annual flowers in your garden

Flowers from Seed

By Amy McDowell

I turned my nose up at zinnias for years. I thought they looked gaudy—bright pink, orange, and red pompoms and coarse foliage dusty with mildew. One year, however, Grandpa McDowell sprinkled a package of zinnia seeds into his garden. A magnificent swarm of butterflies hovered over his garden when we visited on the Fourth of July, and that vision has forever changed my opinion of zinnias.

Raid the seed rack at your local garden center, and you can broaden the spectrum of delight in your garden. There are all kinds of annuals that are not offered in plant packs, but are simple to grow from seed. Annual flowers will not only give your perennial garden continuous color, but they can give it a full, gushing-with-blooms cottage garden look.

Flax, cosmos, and nigella (Love in a Mist) are delicate looking, and you can sprinkle the seed around your perennials to create drifts of color from one end of the bed to the other. Flax creates a wispy hint of color. Blue is the most common, but it also comes in bold yellow and pink. Cosmos blooms are a little more defined in the garden; they come in pink, red, white, and newer yellow and orange varieties. Nigella has feathery foliage and pastel blooms in blue and pink.

Datura and cleome are a couple of giant annual flowers that you can count on reseeding in your garden year after year. Datura have huge five to eight-inch trumpet blooms in white, lavender, and yellow. The standard white ones are sweet smelling, kind of like Fruit Loops. Cleome, sometimes called spider flower, comes in pink, lavender, and white.

Four O’Clocks open their blooms in the middle of the afternoon, hence their name. They come in terrific pink and yellow colors, and form a rounded, knee-high mound. They will also reseed and create large drifts in your garden if you’ll let them.

If you have a hot spot that just bakes in the sun, try poking a few nasturtium seeds into the ground. The first time I grew nasturtium, I planted them in a two-foot square patch between the garage, the driveway, and a sidewalk. It was a southern exposure that was far from the garden hose, so they got little care, but they thrived.

All of these annual flowers can be sown directly into the garden in early May. Annual flowers pollinated by bees, birds, and butterflies in the garden will often lose their boldest colors as they reseed over the years. When the colors start to look watered down, some gardeners hoe the seedlings under in the spring and plant new seed. It’s always delightful to try something new in the garden, and seeds are an inexpensive and fun way to experiment.