The Four Key Ingredients of Container Gardening Potting Mixes
Container Gardening is the most popular form of gardening in the world. Container gardening allows for gardeners to take advantage of every square inch of available space to grow beautiful seasonal flowers, tasty herbs or productive vegetables. Prior to planting in the container of choice – which can range from beautiful ceramic or terra-cotta to half barrels to plastic 5 gallon buckets – there must be discipline in the soil selected to accommodate the selected plant. That is the focus of our content today: to know potting mix components.
Most potting mix soils manufactured today primarily focus on porosity and drainage. Container soils that do not drain efficiently create an environment that contributes to bacterial and fungal diseases which shorten the lifespan of plants and never allows the plant(s) to thrive. We, as gardeners can control how much water we apply during hand watering. But during periods of heavy natural rain, containers can become waterlogged if the soil does not drain, and that begins a downward spiral that leads to disappointing performance.
Harvest’s potting mixes are manufactured using components that contribute to the beneficial movement of water through containers during wet times, and in opposite conditions, are capable of holding moisture during dry periods. Potting soils are very much like a jigsaw puzzle; all the particles in the soil must connect to each other and contribute to the completed puzzle. Four primary soil components create this potting mix jigsaw puzzle:
- Aged Pine Bark Fines- From the bark of Southern Yellow and or Loblolly Pine, we place bark fines in composting windrows for many months until specific temperatures are reached and the bark has aged as indicated by physical and laboratory testing. Aged bark is critical because of its increased water holding capacity. Some soils are made using “green” bark that is not aged and because green bark does not absorb water, the water just runs off of the product and there is minimal absorption. In comparison, aged barks performs like thousands of little tiny sponges in the soil, absorbing moisture when wet, then slowly releasing moisture as the soil dries. But most important for aged pine bark fines is the unique particle size and shape that allows for air to circulate through the soil, providing oxygen to the roots.
- Peat Moss- When blended in perfect proportion with aged pine bark fines and compost, peat moss is an asset to containers because of its moisture holding capacity and porosity. But when not co-mingled perfectly, peat moss does become hydrophobic and actually repels water. The pine bark and compost compliment peat moss by sharing its water holding capabilities.
- Compost- Compost is used for many reasons but primarily for providing natural organic matter which is immediately available to the plant due to the nitrogen and phosphorous forms being quick to break down and available to the plants. Compost also has excellent water holding and particle size that helps with oxygen exchange.
- Perlite- Perlite is eye candy to container gardeners. Its rounded texture adds to porosity and air flow through the soil. The one downside to perlite is its heavy carbon footprint. Therefore most professional growers would exchange aged pine bark fines for perlite as they deliver equal results with lower environmental impacts.
TROUBLE SHOOTING CORNER: If, when you water a container, the water just runs down the sides and out, that soil has become hydrophobic and this was likely caused by the peat moss. The solution? Water slowly and with warm water and this will get the mix out of this state. Learn more about Container and Potted Plant home gardening.
Looking for a great potting mix?
Selecting a potting mix is similar to buying shoes: once you know your needs (flowers, vegetables, herbs, or tropical) you need to try the mix out to make sure it fits your needs. Many experienced gardeners modify standard mixes for specific plants, but buying high quality potting mixes as Harvest produces – see our Superpowered Organic Potting Mix with Organic Fertilizer and our Nature’s Pride Select Organic Potting Mix with cow fibre for examples – will provided you with a decided growing advantage immediately.
By Dave Devine