Soil Types . . .
Soil Types - Clay, Sand, or Loam? - What type of soil do you have? Some of us in Harford County and the surrounding areas have clay soil. It may not be Georgia-red clay but a light-colored clay. Clay soil has very fine soil particles, bakes to a hard, cement-like consistency during droughts, remains cold and wet longer in the spring than other soil types, and if you squeeze clay with some moisture in it, it will squeeze into a tight ball. Clay soil is also very heavy so digging is hard work. I use a smaller shovel which is a lot easier on my back.
- Clay soil can also have organic matter (loam) mixed with it. You can tell somewhat if the soil has organic matter if it is heavy and also dark in color. As I have been adding organic matter to our clay soil for many years in the large back bed, it is no longer light clay in color but much darker as well as softer and easier to work. This organic clay layer is now eight to 12 inches deep.
- Sandy soil has large soil particles, always remains loose even when squeezed into a ball, warms up fast in the spring, and doesn't retain water. I feel that sandy soil is the hardest soil to work with because it dries out quickly. Care must be taken to use only those plants that grow well in that type of soil. If you live to the east of I95, your soil is more likely to be sandy or has some sand in it.
- Loamy soil is a mixture of the two soils and also has organic matter. Organic matter is decayed or decaying material such as leaves, rotting trees and tree roots, living or dead creatures, manure, etc. Some of my clients are lucky to have loamy soil. It holds moisture, isn't too heavy, and azaleas and rhododendrons love this soil.
Amending Clay and Sandy Soils - Clay and sandy soils need to be amended to grow perennials and small shrubs. If your soil is not a loam type soil and you do not want to amend the soil as you plant, then plant those plants that will grow in that type of soil. You'll find your choices somewhat limited. Check the "Soil Requirements" column in my section "Plants for Clay Soil". Above each of the plant listings, I explain what the words used in soil and light requirement columns mean.
For More Information? - Contact the University of Maryland Extension Service if you need more information on soils - see my Links Page for the web address.
As a general rule, for plants to be planted in the ground, the minimum temperature zone for the plant should be Zone 6. For plants to remain in pots outdoors through the winter, the minimum temperature zone for the plant should be Zone 5. I know from experience that my garden gets frost whereas other closeby areas do not, so I am careful to pick plants for Zone 6 and colder.
Soil pH . . .
Is Your Soil Alkaline or Acidic? Soil pH indicates the alkalinity or acidity of the soil. Test kits are available for gardeners to test for soil pH. The pH scale ranges from 0 which is very acidic to 10 which is very alkaline. A level of pH 7 indicates the soil is neutral - neither acid nor alkaline. Soil pH is important because some plants will only thrive in soils within a specific pH range. Most plants grow in a pH range of 4 to 8. Ericaceous plants (rhododendrons and azaleas) prefer acidic or low pH soils. Often, herbs and vegetables prefer alkaline soils (pH 7 or higher).
Soil pH in Harford County, as well as in the eastern half of the United States, has low soil pH ranging from 4 and up. We can grow a variety of plants if the soil drains well. We can grow azaleas, rhododendrons, herbs, vegetables, annuals, perennials, and bulbs. A soil test will help you determine your soil's pH; the kits are sold in most large garden supply stores.
How to Plant Trees, Shrubs, and Perennials
Check for Soil Drainage - After we've done our homework on plant selection and have purchased our plants, now we're ready to plant. Before planting, though, dig the planting hole and fill it with water and watch how fast the water drains from it. If the hole drains within an hour or two, then that area has well-drained soil. If the water doesn't drain at all, then you'll have to correct the problem before planting plants that require well-drained soil. Another way to get around a poorly-drained site is to plant plants that want boggy or wet soil and there are many of them that like such conditions. If you need a list of plants, check the web for lots of information on this subject. One such site is from The Pennsylvania State University extension service.
We will assume that the water in the planting hole drained away within an hour or two and you're ready to plant.
Trees and Shrubs:
- Plant trees and large shrubs such as viburnums and maples in non-amended soil as dug from the hole. Dig the planting hole the same depth as the plant's root ball and two times wider. If the plant requires well-drained soil, I make three or four holes in the bottom of the planting hole with a narrow-blade screw driver so that water will drain away from the bottom of the hole.
- Remove the plant from the container and check the plant's soil mixture. If it's bark mulch, remove as much of it as possible. Cut three or four vertical slits into the root ball and rough up the roots on the outside of the ball.
- If the roots seem dry or the ball is full of roots, place the plant in a container of water so that the roots soak up water.
- After removing the plant from the water and draining it, plant the plant, filling one-third of the area around the roots with soil and tamping down the soil.
- Soak the soil with water.
- After some of the water has drained away, fill with the rest of the soil.
- Place two to three inches of mulch on top of the soil, keeping the mulch away from the plant's bark.
- Then water the plant again until water doesn't enter the planting hole any more.
Small Shrubs and Perennials:
- Small shrubs and perennials are usually planted in amended soil. I amend clay soil with up to one-third of the soil's volume with peat moss or compost. I also often mix in a couple of handfuls of perlite, a natural soil amendment. The peat moss and perlite help to make the soil drain faster. The peat moss holds moisture too. By the time I'm done, the mixture is the color of coffee grounds instead of clay. If you're using compost instead of peat moss, only use up to one-quarter of compost by volume.
- Make holes in the bottom of the planting hole for plants needing well-drained soil.
- If the root ball is rootbound, loosen up the roots on the outside of the ball and make three or four vertical cuts into the center of the ball so water will get into the roots.
- If the rootball is very dry, soak it in water and drain well.
- Then plant as above for trees and shrubs.
- Mulch the plant with one or two inches of mulch, keeping the mulch away from the plant's stem.