Answer: Manure tea is made by soaking several shovel fulls of aged manure in a bucket of water for several weeks. It is then used as a foliar feed for ornamental plants. It should not be used in the vegetable garden.
Poor soil can be improved over time with additions of organic matter such as compost, aged stable manure and bedding, rotted leaves, or any other organic material you have available. A twelve inch deep layer worked into the top twelve inches of soil would not be too much for truly poor soil. A clay based soil may also benefit from the addition of a small amount of sand. With truly terrible soil, using raised beds may be worth considering, depending on what you want to grow. Finally, many plants will tolerate less than ideal conditions, so a careful plant selection process to match plants with the growing condition can be valuable.
You might also want to run some basic soil tests if you haven't already, and see how the nutrients, pH and so on really are.
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