Most gardeners aren't blessed with perfect soil. For many of us the addition of composted material, gardening lime and peat will be all we need to grow fruits and vegetables in our gardens. If you're new to gardening or you aren't getting the results expected, give these steps a try to better prepare your soil.
Test for pH and nutrient content
One of the first things you should do prior to digging up weeds and tilling your soil is to test it for pH and nutrient makeup. This can involve a simple kit available at most hardware and gardening stores or a more sophisticated test mailed into your state's agronomics services department or local county extension office. There are also private labs that provide this service. The home testing kits have worked fine for us, however if you have major issues with your lawn and gardens, the more sophisticated testing is probably in order.
When testing soil, be sure to take samples from different areas of your garden. This is especially important if you have a variety of beds or a very large plot. This will allow you to amend the soil if necessary to fit the needs of the plants going into that particular bed or section of the garden.
Don't skip this step. It will save you money by preventing the purchase of unnecessary soil additives or those that are wrong for your soil type. Why add products to correct something your soil isn't missing? A $20 test can help save you money and make your garden more productive.
Remove weeds
Never let weeds go to seed in or around your garden. Even if you are letting part of your garden go fallow for a year, keep the weeds cut back and dig up those with large tap roots. Weeds like dock and crabgrass can spread with just a small section of root or stem left in the ground. The best method to control these plants is to dig them up with a shovel and remove as much of the root as possible.
Once you've removed the weeds that have gone to seed or that spread through root propagation, till remaining weeds into the soil. Uprooting weeds will kill them and most will return nutrients to the soil as they decompose.
Chemical weed removal adds toxins to the soil, air and water table. They are harmful to humans and animals who come in contact with the sprays during and shortly after application. I do not recommend their use in or around a garden where you grow food for human consumption.
Loosen the soil
Hard, compact soil doesn't give the tender roots of young plants much room to grow. Whether you use a motorized tiller or shovel and hoe, your garden bed needs to have the soil loosened enough to encourage root growth. If you are clearing a large area initially, you can hire someone to break the ground with a large tractor or you can rent a larger rear-tine tiller. Once your garden has been worked, it may be possible to maintain it with a much smaller, easier to manage tiller.
Don't buy too much tool for the job. Rent equipment or hire out jobs that require equipment you will only use a few times. Don't buy a powerful tiller for raised beds, especially for those you add purchased soil to each year. A shovel, hoe and strong back are all some raised beds need. Others will need a small electric tiller. My Honda tiller was $350 and while it is small for the area I garden, the price of the next size up was too much for my wallet. When I need to break ground for a new bed, I hire out the job after I've removed the weeds.
Regardless of your method, it is a good rule of thumb to dig or till to a depth of six inches. For root crops you will need to go even deeper. Many carrot varieties will need a depth of eight to ten inches. If your soil is very compact you can mound the soil to help get the right depth for carrots, potatoes and other root crops.
Enrich the soil
After testing you should have a good idea about nutrients you need to add to your soil. If you don't have any specific issues you can use cow, horse or chicken manure for general purpose boosting. You will need one bushel of chicken manure per 100 square feet or four bushels of cow or horse manure for the same space. My large vegetable garden is 1800 square feet. Buying bagged manure runs about $150 each year. It is much cheaper to buy manure from one of the local farmers, but you have to make sure the manure has been composted prior to use. Don't add fresh manure after your garden has been planted.
Soil pH
Most vegetable plants prefer a soil pH range of 6.0 to 6.8. Soil pH measures the acidity or alkilinity of your garden bed. It is measured in a range of 0 to 14.0 with lower numbers representing higher acidity and higher numbers representing higher alkilinity. A pH of 7.0 is neutral. The Old Farmer's Almanac has a great resource for checking pH needs of a variety of trees, flowers and vegetables.
If your soil is too acidic you can add gardening lime to raise the pH and if it is too alkiline you should add gypsum or ground sulfur.
Potassium
Potassium is important for general plant health. If it is deficient in your soil you can add it back with composted material heavy on fruit plant waste. Produce that is naturally high in potassium like banana peels, citrus rinds, and tomatoes are great for compost that is rich in potassium. You may also use ash from burned hardwoods. Make sure the ash is from a fire where no accelerants were used or where yard waste was burned. Ash from these fires will have chemicals or other undesireable materials in them that you don't want in your garden.
Potassium can be introduced in the form of a chemical fertilizer, but it can burn your plants. Organic fertilizers break down in the soil over a longer period of time providing a natural time-release feature.
Nitrogen
Plants use more nitrogen than any other nutrient. Each year I use grass clippings inbetween bed rows to help control the weeds. They add nitrogen back to the soil as they decompose. Rich compost will add nitrogen back to the soil as will cover crops, but if you need a quick boost of nitrogen use blood meal. While it is organic, it can burn plants if applied in certain conditions. It should be applied to the soil and washed from plant leaves to prevent damage. Bean and pea varieties fix nitrogen in the soil for use by plants that follow it in a rotation cycle.
Phosphorous
Phosphorous is important for root growth and to promote the setting of fruit and flowers. You can add phosphorous back into the soil through the application of animal manure or blood meal.
While there are other macronutrients that are important, those listed above are most commonly found to be lacking. For more detailed information on soil nutrients specific to your area, check with the state extension office closest to you. Most states offer free information through their agricultural office or local county extension offices.
Crop rotation
One way to reduce the depletion of nutrients from your soil is to rotate crops to alternate the plants that deplete the soil of nutrients with those plants that return nutrients to the soil or that deplete different nutrients from those crops planted in prior years. Another reason to rotate crops is to reduce diseases and pests that afflict plants in the same family.
It is important to understand the nutrient needs of each crop you plant. You should also understand which nutrients they strip from the soil. Proper crop rotation can save you from having to add more nutrients back into the soil than necessary, which saves time and money. For good guides to crop rotation check GrowVeg.com, OrganicGardening.com, or this report from North Carolina State University.
Green manure
Green manure consists of plants like borage that are planted toward the end of the growing season and left in the garden to help maintain the soil structure and prevent erosion. They are then either scraped or pulled from the garden and added to a compost pile or they are tilled under directly into the garden. If tilled under you will need to wait 30 days before planting again. Mother Earth News has an excellent guide to using green manure.
