Soil and Amendments
Starting with Soils
So, you've stepped into your local garden stores and you're staring down the aisles of soils, fertilizers and amendments and starting to feel overwhelmed. Fear not! Many of the mixtures you're staring at are different variations of the same basic components.
Top Soil - Top soil is often the equivalent of native soil. There's very little benefit to using this for gardening, except occasionally for leveling the ground. It contains very additional few nutrients or organic material to help your plants grow.
Raised Bed/In-Ground Soils - Soils labeled for Raised Bed and In-Ground use are often a middle-ground soil. They are often cheaper than a potting soil, but generally they have less moisture holding capability and bigger chunks of organic material like bark and sticks. Generally, you should not use this for a container garden, nor for the top twelve inches of a raised bed, unless you ensure that the mix has been filtered for the majority of sticks and bark. A small number of sticks and bark is okay, but a high percentage of hard materials will slow down your plant's growth over the season, because your plants are going to spend some of their energy breaking down that organic materiain the soil, rather than putting their energy into producing fruit, foliage, and roots. These soils are however great for layering in for filler on the bottom of a taller raised bed.
Potting Soil - Potting soils are ideal for containers and the top twelve inches of a raised bed. These are generally a higher quality, have additional nutrients added, and have additional moisture-holding capabilities than native soil. A higher price is often an indicator of quality, but sometimes, the price is misleading. Look for a soil with a deep, dark color and a limited number of hard materials like sticks and bark.
Seed Starter - Seed starter mixes usually are not true soil. Usually, they are a mix of coco coir/peat moss and perlite/vermiculte. What this means is that seed starter contains virtually no nutrients and is purely designed for maintaining an even level of moisture for a longer period of time. This is not suitable for in garden use. This is purely for starting seeds up until they produce their first set of true leaves. After than point, seedlings need to be moved into true soil.
Amendments and Fertilizers
Alright, so you've picked your soil. What's it mean to amend the soil?
Well, what this means for you is going to depend on your individual situation. You'll need to evaluate your soil determine what might be necessary for your garden. The good news is most ferilizers are going to tell you exactly what they provide for your plants in the form of three numbers on the bag (e.g. 10-10-10). The three numbers represent the Nitrogen-Phosphorus-Potassium (N-P-K) ratios of that particular fetilizer.
The short version:
Nitrogen, the first number, is going to promote the green growth of leaves.
Phosphorus, the second number, supports the growth of flowers, fruit and the roots.
Potassium, the third number, supports the roots and the stems.
Often, for plants the produce non-leafy foods like tomatoes, peppers, etc., having a fertilizer with more nitrogen in the beginning helps the plant get established, but switching to a fertilizer with higher phosphorus and potassium may be best for supporting the plant when it's producing food.
Here's a few of the many options:
Synthetic fertilizers - These are fertilizers like Miracle-Gro that use synthetically created nutrients in high amounts to feed plants. The high amounts of the nutrients allow the plants to grow faster and bigger than natural fertilizers. This is great for new gardeners as it allows you to get a large harvest without needing to use many different types of fertilizer, but it does have a few drawbacks. Often these fertilizers don't contain all of the micronutrients plants need, and therefore, your produce may not be as nutritious as organically grown produce. It also may "burn" the plants roots if you use too much, causing the plant to regress in its growth.
Compost - This is one of the most important natural amendments you can add to your soil. In addition to providing the major N-P-K nutrients, well-made compost contains the necessary micronutients and minerals a plant needs to grow and improves overall soil structure. If your soil feels sandy in nature, it may lack the necessary nutrients and structure to support your plants. Adding compost can greatly improve your chances of a successful crop. (Tip: Combine multiple types of compost to ensure that your plants have access to all the miconutrients they need.)
Bone Meal - Bone meal adds additional phosphorus and calcium to the soil. This is great for fruiting plants, like tomatoes and peppers to prevent the bottoms of your fruits from rotting. (For more information, look up Blossum-End Rot.)
Blood Meal - Blood meal adds natural sources of nitrogen and micronutrients to the soils.
Perlite/Vermiculite - Perlite and Vermiculute are crushed bits of volcanic rock that improve the overall drainage of a soil.
Coco Coir/Peat Moss - Coco coir and peat moss improve the soils ability to hold water.
Worm Castings - Worm castings are a type of compost that utilizes worms to break down the nutrients into a form that plants can absorb.
Mushroom Compost - Mushroom compost is a byproduct of mushroom production that is an excellent source of nutrients for a home garden.