soil improvement

Designing A Garden For Heirloom Plants

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Winter is an excellent time for gardeners to plan garden designs as there is minimal activity outside this time of year, epecially in northern climates.  As soon as soil can be worked you can begin executing your project.  In southern and low desert climates it is also a good time to plan your garden and build it because the cool temperatures make it easier to do heavy physical labor.

This last year I designed and built a garden in Early American style to hold my collection of antique roses, fruits, flowers and vegetables.  I had several goals: create a design based on historic models; maximize use of space and efficiency; minimize maintenance labor; use local materials, protect plants from predation and create the best growing conditions possible.  The first picture above depicts an American garden design plan from the late eighteenth century.  The original drawing is archived at the Essex Institute in Salem, MA.  My photo is taken from British and American Gardens of the Eighteenth Century, edited by Robert P. Maccubin and Peter Martin; The Colonial Williamsburg Press, 1984.  This style of design and use of space has its roots in Medieval gardens of Europe.  The plan is formal; beds are edged by timbers, are often raised or slightly raised and mud-free (and/or weed-free) paths separate beds.  This formal style is quite convenient to tend: crops can be separated and rotated; soil pH, texture and drainage can be adjusted from bed to bed, and some beds can be high water-use, while others may be medium or low water-use.  I find it convenient to place high water-use beds nearest the house and low water-use beds farthest away.

The second photo above is of my garden design for my garden in Corvallis, Oregon.  I measured the entire site, then made the drawing to scale on graph paper.  I used cut-out pieces of colored paper for structures such as the greenhouse, cold frames and porches.  I made labeled pieces of graph paper to indicate trees and shrubs.  The cut-out pieces can be moved around over the drawing until you determine where you want everything to go.  Shade is an issue in this garden, so sun-loving and shade tolerant plants were placed accordingly.

When the design was finished, trees and shrubs that cast heavy shade were removed or moved to new location; materials and workmen were sourced.  Tree and shrub roots were ground and removed.  Soil leveling was undertaken, then fences were built.  We tilled the soil, as seen in the third photo above, then raked the grass and roots into piles approximating the location of beds.  We had such a hot summer that the grass roots quickly died.  They provided immediate organic material for the soil.

We measured and drew out my design with spray paint and began to build our boxed beds.  I used 2′ x 12′ cedar lumber anchored in place with metal spikes set in concrete.  The fourth photo shows bed construction in the back yard garden.  Trenches 6 inches deep were dug to lay the timbers into.  Now we had beds raised six inches above the original soil level and 4 inches above planned level of the gravel.  This enabled us to use the native soil and amend it with 4 to 5 inches of compost, manure, greensand, wood ashes, alfalfa meal and bone meal (See the fifth photo above of the front garden).

After soil preparation, planting could begin.  The sixth photo above is a shot of the back garden two weeks after planting.  Vegetables grew quickly in the wonderful, organically amended soil.  The front garden was finished and planted a few weeks later (the seventh photo above).  The front beds were planned for bulbs, perennials and shrubs that use little or no additional water in our climate.  I do have to water the rose bed bordering the fence; watering deeply but infrequently once the roses are established.

The last photo shows one of the large 3′ x 3′ wooden tubs newly planted with ‘Blue-Podded Blauwschokker’ peas, which date to the sixteenth century.

The entire construction project took six months, from design to planting.  For a labor force we had two people working part time and one person working full time.  The garden is planted with heirloom plants dating from the ancient Greco-Roman period through the Oregon Trail Era (1830-1869).  Also included are a few more recent varieties, dating before and up to 1925, when the house was built.

 

IMPROVING YOUR SOIL

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The quality of your garden soil is an important consideration in growing heirloom fruits, vegetables and flowers as soils come in a wide variety of textures and materials.  Soil texture describes the size of the mineral particles in your soil.  Soil particles in order of size, from smallest to largest, are: clay, silt, fine sand, medium sand and coarse sand.  The ideal garden soil (for most plants) is a loam soil, which carries particles of clay, silt and sand, plus organic matter.

Soil structure refers to the way soil particles bind together to form clumps.  In soils with good structure the spaces between particles are large enough to ensure good drainage but do not dry too quickly.  The best garden soil, loam soil, drains fast enough for root health but retains enough moisture for continued satisfactory growth.  Adding amendments to soils will improve its structure and provide food for beneficial microbes.

Another consideration to address before you add amendments to the soil is to test the pH— the measure of acidity to alkalinity in your native soil.  A pH of 7 is considered neutral and many plants are adapted to this condition.  A pH above 7 is considered alkaline while a pH below 7 is considered acid.  A pH test can serve as a guide to which plants you might be able to grow with ease and others that might be more difficult.  It is easier to make soils more alkaline, but difficult to acidify them.  Even though you may add sulfur or aluminum to your soil to acidify it, the subsoils beneath will remain alkaline and eventually the alkalinity will return, especially if your water is alkaline.  This makes it difficult to grow plants such as camellias, rhododendrons and azaleas (which prefer acid soil) in regions with alkaline soil and water.  Adding lime or crushed shells to acid soils will increase soil alkalinity.

One consideration in growing heirloom plants is to research soil amendment ingredients and practices used in the 19th century, as most of the plants still in existence from that era and before were selected under those soil conditions.  I am an organic gardener using these time-tested methods and believe that building your soil is crucial to long term success.  By amending your soil with such things as greensand, sulfur, bone meal, kelp meal and manure, you will enrich it and create a productive environment for soil bacteria.  You can choose from composted cow, hog or horse manure, alfalfa meal, cottonseed meal and guano or chicken manure to add significant nitrogen to your garden soil.  These all contain small levels of potassium and potash.  Bone meal, hoof and horn meal are excellent sources of potassium.  Kelp meal, wood ashes and greensand are significant sources of potash.  Greensand also contains many trace minerals.  Keep in mind that bone meal is somewhat alkaline and wood ashes are quite alkaline.  Home made compost is always valuable and usually contains a fair amount of nitrogen with smaller mount of potassium, potash and trace minerals.  Another option to improve soil is to plant cover crops and till them under.  Clover, rye, lentils, field peas, vetch and buckwheat are some examples.

This is the time of year to plan for improving your soil.  As soon as the ground thaws you can test the pH and as soon as soil becomes workable (not too wet to dig) you can add amendments.  It is important to learn as much as you can about what type of soil each plant you plan to grow prefers, for long term success.  For example, brassicas (cole crops like cabbage) have fewer pest problems and greater production in slightly alkaline soils.