Working with clay soils
Presented by Wendy Maddox
 

Rule # 1

Never work with clay soils when they are wet. This will destroy the structure, causing it to bind together like cement and it is very hard to bring it back.

Rule # 2

Aim to add about 30% organic matter to it before initial planting. This will aid in nutrient retention and availability by allowing air and water to move freely through channels which are created by both living soil organisms and decaying roots and vegetative matter. Soil needs to breathe to live and erosion will also be reduced by the better absorption of water.

Sources of Organic Matter

1. Old hay left from last year-get it soon and leave it uncovered so that it will start to rot and any seeds can germinate and then die. I put up to 40 bales a year on my first vegetable garden (which was pure, sticky, red clay) and after six years it was the best soil ever. Stop at your local farmer who has cows or sells hay and ask him if he has any rotten bales. The big round bales are difficult to work with but if It is all you can get- take it. Bear in mind that farmers do have time, effort and money in their crops and should be paid just like everyone else for their labors. Support your local farmer. You can get fresh hay for $2.50 a bale so maybe you can get old stuff somewhat cheaper. Big bales go for $15.00 to $25.00 each.

2. Shredded hardwood bark mulch- this turns to black scrumptious soil in one year but it is never wasted. If it does not rot in your garden you may have a problem with not enough soil organisms to break it down which can be caused by drought, chemical fertilizers (which have burnt your soil critters up) or an imbalance of nutrients. Get your soil tested! Fresh wood chips sawdust depletes nitrogen from the soil and will steal it from your plants too.

3. Manure and bedding from animals-If possible get this months in advance of using it and let it compost so their will be no danger of burning tender plants or roots. I usually pile my barn cleanings up one spring and use them the next Fall Winter/ Spring. This also turns into really black, crumbly soil with no bad smell at all. I use hay as bedding in my barn just because my horses, sheep and chickens waste a lot. This is called the deep litter method- it actually composts a fair amount over the winter while throwing off a little heat for the animals to lay on. Most horse barns use sawdust but it comes already mixed with its' needed nitrogen. I would still compost this some first.

4. Crop residues and Green Manures-Legumes such as alfalfa, soybeans, cowpeas will help to fix nitrogen from the air into the soil if you work them in with a tiller or turn them under. Do not forget to get the inoculants when you buy the seeds. Dampen the seeds in a bucket with a small amount of water and stir the inoculants in with them so that it will stick. Cool season grasses such as rye or winter wheat will add lots of carbon, nutrients and fibrous roots which create channels in the soil and feed the soil organisms which in turn will help to feed your plants. Even if you mow them down or graze them some the roots still add considerable organic matter to the soil.

5. Composted Household vegetable waste- Mix with fresh grass clippings, shredded leaves and garden clippings for a good source of fresh lively microbes and nutrients that will make your earthworms very happy too. Chemical fertilizers are rough on your worms too.

Other factors affecting your soils

PH of soil is affected by rainfall - high rainfall amounts such as we have here leach away calcium and magnesium and so our soils tend to be acidic unless they are in direct contact with leaching limestone. Soils that are at the extremes of the PH scale can lose their structure and also make it impossible for mineral nutrients that are present to be actually taken up and used by the plants.

Iron, manganese, copper, zinc & boron may be unavailable in strongly alkaline soils, while calcium & molybendum may be unavailable in very acidic soils. Phosphorous can be unavailable at both extremes. Again, a soil test will let you know where you stand on this.

Lime is added to soils to raise the PH and Sulfur is used to acidify alkaline soils. Most garden plants like the PH to be in the neutral (7) to slightly acid (~6.5) range except such plants as blueberries, rhododendrons and azaleas which like it as low as 4.5-5.5.  The PH level can also affect plant diseases. For instance, potato scab is less severe in acid soils and club root of the crucifer family (broccoli, cabbage, cauliflower) may be helped by lime applications. Wood ashes can also be used to sweeten or reuse the PH while at the same time adding phosphorous to the soil. You do need to be aware that both lime and wood ashes can be caustic so it should be applied right before a rain if possible. Too much Nitrogen can cause carrots to split, apples to have low color, delayed ripening of tomatoes and heavy vine growth, and a reduction in flowering and fruiting of ornamentals.
The Phosphorous in Rock Phosphate will never decompose if the pH is 6.5 or higher so it would be a waste to put it down without checking and adjusting the pH first.

Steep Grades or erosion Problems can be helped by never leaving your soil naked and exposed. Keep it covered by mulch or a cover crop as much as possible. If the area is a steep grade and you are trying to establish cover lay down some sisal netting or terrace the slope with a series of low retaining walls made of rocks or wood to slow down the passage of water across it and plant things that root well and tolerate poor conditions like daylilies or liriope and then mulch them well. Water with soaker hoses until established or during a drought as it will slowly soak in instead of running off. A timer set up on the hose bib will automatically turn it off for you after a few hours. Retaining walls are also a rest garden design element which can define an area and create visual interest while showing off the plants. Plus you can sit on them and survey your work and pleasure.

Don't forget to enjoy your garden. Try and see the beauty and relax in it while drinking your lemonade or your morning coffee. Don't worry about what has not been done- next year will always be better than the last.
 

Soil Amendment Tips from the Andre' Viette Gardening Guide 2001 www.viette.com 1-800-575-5538

For each lOxlO foot area of garden space add and till in:

1. 5-10# of Plant Tone for Sun or 4-7# Holly Tone for shade (slow release organic fertilizers which will not burn the roots)
2. 5-10# Rock Phosphate for sun or 3-5# super phosphate for shade (promotes root growth and flowering as opposed to vegetation)
3. 5-10# greensand (contains nutrients for disease resistance and minor elements)
4. 5-10# gypsum depending on heaviness of soil (a conditioner especially for clay)
5. For heavy clay add the "Clay Buster"PermaTill for info 877-PERMAT1L
6. 2# of 8 month Osmocote or Sierra fertilize (optional, slow release pellets)

This Catalog is excellent this year with all kinds of plant lists for specific areas and soil conditions, design help and great perennials. Also their gardens are beautiful to look at and wander through. They are straight down I81 near Staunton Va-about a 21/2 hour drive. They also ship UPS.

 
 
 
 

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