Most gardening practices, especially those with containers, makes use of some type of potting medium. Generally, this takes the form of soil and additional additives that promote adequate plant growth. However, some gardeners prefer to use soilless potting mix. Gardening with soilless mix simply means that the plants are grown without the use of any soil.
Instead of soil, plants are grown in a planting medium that consists of various organic and inorganic materials. Since it does not contain soil, which is more prone to carrying harmful bacteria and fungi, soilless mix is oftentimes considered sterile. This makes it especially good for plants, as there is no worry of any harmful diseases or pests.
The only downside to using a soilless mix is the fact that fertility levels may be lower. Therefore, additional nutrients such as lime may be needed. Many times a nutrient water solution is used to fertilize plants. This is especially true of hydroponically grown plants. The use of slow-release fertilizer is another alternative for supplying plants with nutrients.
Some of the more expensive bags of soilless mix may already contain fertilizer. These mixes are available at most garden supply centers and can also be prepared at home. Soilless potting mix can be blended with various materials to improve drainage, water retention, fertility, etc. There are numerous recipes for preparing these mixes.
Most types of soilless mix contain peat moss, coarse sand, perlite or vermiculite in some degree. Sphagnum peat moss is one of the more ideal potting media used. Peat not only holds water well, but also drains easily. It is also lightweight and inexpensive. In addition, this type of medium is slightly acidic, making it great for seed starting.
Sand is sometimes added to soilless mix for drainage. However, perlite, which is commonly found in many types of potting soil, is another option. These small, white pebbles can also provide adequate drainage while retaining water at the same time. Vermiculite is a silvery-colored mica material that works much like perlite. This type of medium compacts more easily and is less often used.
Other materials that can be added to soilless mix include bark and coconut coir. Oftentimes bark is used to improve drainage and promote better air circulation. Coconut coir is similar in nature to peat moss but not quite as messy. Occasionally, some gardeners prefer to add small amounts of compost to their soilless potting mixes.
Soilless mix is popular with hydroponic gardeners. While there are just as many recipes for soilless potting media, the use of lava chips, which are similar to bark, and vermiculite are common. Perlite and coconut coir are oftentimes used as well. Plants grown hydroponically are always given a continual supply of nutrient solution to encourage healthy, vigorous growth.