Organic gardening brings benefits to both you and the plant. In order to achieve the lush, productive garden of your dreams, you'll likely have to amend the soil to add the nutrients that ornamental and edible plants need to thrive. Bone meal and blood meal are two fertilizer options that come from natural sources, enriching soil with nitrogen and phosphorous.

Bone Meal: Phosphorous for Root Development

Long before synthetic commercial fertilizers were available, farmers turned to bone meal to enrich soils in need of amendment. Bone meal is made from steamed and crushed animal bones, and is rich in phosphorous, a mineral that plants need for healthy root development and flower growth. It also contains calcium and a little bit of nitrogen, both of which are beneficial to plants. Bone meal is taken up by plants slowly over time, so as long as it is used sparingly, there is little risk of 'burning' plants with too much of this fertilizer.

That makes bone meal an ideal supplement for bulbs and roses in particular, which flourish with an extra boost of phosphorous. A little bit goes a long way, so just one tablespoon is needed for every two square feet. When planting bulbs in the fall, ensure that their spring blooms will be spectacular by adding 1/2 teaspoon per plant to the backfill soil. You can also mix bone meal into the top one to three inches of soil in the spring for other plants.

Some gardeners are concerned about the use of bone meal due to the perceived risk of contaminating the soil or plants with prions, proteins from cow bones that cause bovine spongiform encephalopathy (BSE), better known as mad cow disease. Experts say this isn't a problem, but you can always seek out bone meal that isn't made from cows. Scotts Organic Choice Bone Meal is made from non-cow sources.

Blood Meal: Nitrogen for Healthy Growth

It may sound a little macabre, but blood meal is a natural way to boost all-important nitrogen levels in the soil. Without nitrogen, plants simply can't grow. Blood meal is one of the richest non-synthetic sources of nitrogen, which is a crucial component of plant cells and one of the basic components of chlorophyll, the substance that helps plants convert sunlight into sugars. It helps plants grow healthy root systems and produce green foliage more rapidly, making them more resistant to pests and diseases.

Want big, overflowing baskets of fruits and vegetables from your organic garden? Blood meal helps increase plants' yield, adding lots of leafy green growth. This makes it a great fertilizer for nitrogen-hungry greens like lettuce, brussels sprouts and kale. Blood meal products like Scotts Organic Choice Blood Meal should be applied to soil every two months during the growing season, starting in the spring.

Blood meal can also be used to balance the nitrogen-to-carbon ratio in compost piles. 'Brown' materials in compost, like dried leaves, straw and paper, contain carbon, while nitrogen is supplied by "green matter" like fresh or dried plant material and vegetable scraps. Blood meal also helps balance carbon content in mulch to keep nitrogen in the soil at healthy levels.

Like bone meal, blood meal is a by-product of animal processing. Using these substances as natural fertilizers helps ensure that no part of the animals that are raised and slaughtered for the food industry go to waste.