For general garden use, you should add a 2-3 inch layer of well-rotted or composted cow manure and till it into the top 6-9 inches of soil. A specific application rate for a general purpose, commercially composted product is 40 pounds per 100 square feet.
Yes--too much cow manure in a garden can cause problems. Use it, but apply carefully. Nutrient imbalance: Fresh or excessive manure supplies very high levels of nitrogen, salts, and soluble nutrients that can burn roots, inhibit germination, or create nutrient imbalances (excess N causing poor fruiting, for example).
Cornell University recommended 40 lbs of manure per 100 sq ft. Or 0.4 lbs per sq ft. You added maybe 0.1 lb per sq ft. at most. So, you didn't really add a lot. However, usually adding manure is done at the beginning of the season, so adding it as a top dressing may be the problem.
The manure may be spread atop the soil or incorporated into the garden soil. Pig, dog, cat, and human waste should never be used in a vegetable garden. Cow, horse, chicken/poultry, sheep, goat, and llama manure are acceptable types of manure appropriate for use in vegetable gardens.
Surface-level vegetables that do not like manure:
It helps sandy soil hold water and it helps breakup clay soil so plant roots can grow. Fresh manure should be tilled into the soil in the fall, so it has all winter to break down. Fresh manure will burn plants and kill them. Composted manure bought in the garden center can be added right at planting time.
Manure can contain human pathogens and through its use near fruits and vegetables, it can spread human pathogens to produce. Pathogens harmful to humans that are often found in manure include: pathogenic E. coli, Salmonella, and Listeria monocytogenes.
So, the best tomato fertilizer must offer all of these components in the proper amounts and make up for any soil deficiencies. Generally, animal dung from non-industrial farms is the most popular organic fertilizer used in tomato cultivation — cow, horse, and sheep-goat manures work best.
To Minimize the Health Risks Associated with Using Manures in Home Gardens. Wait at least 120 days after applying raw or aged manure to harvest crops that grow in or near the soil (root crops, leafy greens, strawberries). Wait at least 90 days for other crops.
I even put small amounts of the manure directly into my garden in the early spring. It breaks down so quickly that it doesn't hurt the young plants that go out just a few weeks later. However, never apply any fresh manure directly to the roots or stems of plants.
On other edible crops, fresh manure applications should be made at least three months prior to harvest. With just a four month or so growing season, this means you should only apply fresh manure in the fall; not in the spring or during the growing season to any area that is or will be planted with food crops.
Don't:
Perhaps you've heard the expression in which snow is referred to as "poor man's fertilizer." It turns out that this is more than just an "old wives' tale." Snow can actually add nutrients, most notably nitrogen, into the soil.
The best time to apply fall fertilizer is typically from late September through early November, once daytime temperatures cool but before the ground freezes. A slow-release granular fertilizer works best, especially one with a balanced nitrogen content.
Nitrogen excess
Labor Intensive: Collecting, preparing, and applying manure requires significant manual labor. Odor Problems: Manure often produces a strong, unpleasant smell which can be a nuisance. Slow Nutrient Release: Nutrients in manure are released slowly, so it may not meet the immediate nutrient needs of plants.
Green manures are quick growing, so the process is simple. You sow, they grow - and then you dig them in. In just a few weeks green manures can benefit the soil.
Applying manure in autumn allows it to break down and integrate into the soil before the next planting season, providing sufficient time for its nutrients to become available to the plants. Overwintering: Spreading manure in autumn allows it to benefit from the natural processes that occur during winter.
In September, use your abundant tomatoes for fresh dishes like salsa, salads, and tarts, or preserve them by roasting, sauce-making, canning, or freezing; also, tackle green tomatoes with fried green tomatoes or relish while pruning plants to focus energy on ripening remaining fruit.
Baking soda can help tomato plants by deterring some pests (like aphids), controlling powdery mildew by creating an alkaline environment, and potentially making fruit sweeter by reducing acidity, but it must be used sparingly as overuse raises soil pH, leading to nutrient issues, poor drainage, and potential sodium toxicity, so a diluted spray or light sprinkle around the base (not directly on roots) is key.
You should not compost onions, garlic, and citrus peels in large amounts (they're too acidic/repel worms), diseased plants (spreads illness), Black Walnut tree debris (toxic juglone), and any vegetables cooked with oils, fats, dairy, or meat, as these attract pests and disrupt the balance, but many vegetable scraps like peels, stalks, and leaves are great for compost.
Assess the nutrients in your soil
Soils with excessive compost applications, particularly manure, tend to develop high concentrations of nutrients such as ammonium, calcium, magnesium, potassium and sodium. These soils can also develop high concentrations of bicarbonates, carbonates and hydroxyls.
This turning helps “kick start” the naturally occurring microbes that break down the manure. It takes about three months to complete the composting cycle. During the composting process temperatures can reach one hundred fifty degrees and weed seeds that the cows might have ingested are killed in about two days.