Modern Farmer Discussion started by Modern Farmer 9 months ago
The thing that surprises many people about container gardening is that you don’t put your plants in regular soil. That’s because regular soil tends to be too heavy, meaning that it holds the moisture.  And when it comes to container gardening, you’re looking for a growing medium that drains well.  That’s why you’re going to use is what’s called a soil-less mix.
Let me make one note here..

Some experienced gardeners do use regular potting soil that they mix with other ingredients (like sand) to ensure that it’s aerated and drains well.  However, I wouldn’t necessarily suggest this for a first-time container gardener.  Instead, I suggest you use one of the many commercial mixes available.
TIP: If you do decide to start creating your own soil mixes, I strongly advise that you do NOT use soil from your backyard in order to create this mix.  That’s because this soil is likely to carry pests and diseases.
Stop by your local nursery and you’ll discover that there are quite a few different soil-less mixes available.  All you need to do is focus on the part of the label that tells you what the soil-less mix is for, such as seed germination or general growth. If you’re starting from seeds, then you’ll want to choose a product which is labeled germination, plug or starter.
Most of these soil-less mixes are formulated to retain some moisture while still allowing for aeration and drainage.  You’ll enjoy good results if you choose a soil-less mixture that matches with the plants you’re growing. For example, if you’re growing plants that require more moisture (like tropical plants or big, leafy plants), then you should choose a soil-less mix with a higher water-holding capacity.
Here then are the common ingredients you’ll find in these soil-less mixes…
Peat. This ingredient tends to hold the water and make the soil “heavier” (less aerated). Soil-less mixes with a higher peat content work well for tropical plants, those with heavy foliage and others requiring more moisture.

Coir fiber. These are ground coconut hulls that possess similar properties as peat in terms of retaining water. Thus you’ll see some soil-less mixes that replace some of the peat with coir fiber.
Bark.  This ingredient tends to lower the ability of the soil-less mix to hold water, yet it does help with aeration and drainage.  Avoid bark mixes if you’re looking for a seed germination mix.
TIP: Be sure to get your bark mixes from reputable companies only. That’s because a bark mix that hasn’t properly aged can leech nutrients out of the soil.  Worse yet, an untested bark mix can also introduce disease into your container.  On the other hand, using a good bark mix (from a reputable company) is thought to offer your plants some protection from disease.
Vermiculite. You’ll often find this ingredient in germination mixes, since it helps retain water.  If you’re making your own mix, you can add vermiculite to balance out soil that’s too sandy.  Just be sure to use horticulture-grade vermiculite (NOT construction grade).
Perlite. This ingredient improves drainage.  You’ll see formulations ranging from 25% perlite for plants needing more moisture up to 75% perlite for those plants that require a well-drained growing medium.
TIP: If you’re creating your own mix, then you can use builder’s sand in place of perlite.

Wetting agents. This is the ingredient that determines the ability of the soil-less mix to absorb water from the bottom of the container.  The reason this is important is because some plants require that you water them from the bottom of the container in order to avoid diseases like mildew or rot.

You may also find other ingredients in these mixes which improve the nutrients or pH level of the mix, such as bone meal and limestone.

Choosing a Fertilizer

Your soil mix probably includes some fertilizer. However, because you need to water your plants frequently, the fertilizer and other nutrients tend to get washed away quite quickly. The exception is if the fertilizer is a “time release” fertilizer, where just a small bit of fertilizer is released every time you water the plants.  You can also buy a time-release fertilizer separately and add it to your growing media. 
Another option is to use a liquid fertilizer.  You can use a liquid fertilizer as often as every other time you water your plants. However, be sure to cut the fertilizer with extra water so that you’re using a fertilizer that’s 25% to 50% as strong as the regular mix. 
TIP: I you’re using an artificial fertilizer, then make sure your growing medium is damp when you add the fertilizer.  This helps ensure that you don’t burn your plants.

In all cases, you’ll notice that fertilizers contain differing amounts of nitrogen (N), phosphorous (P) and potassium (K).  You’ll use different fertilizer concentrations depending on what you’re growing. You’ll also use different fertilizers at different growth stages.  The label on the fertilizer should tell you how and when to use the fertilizer.  However, here are the general guidelines:

Nitrogen helps promote good growth, especially for lush and leafy plants. Thus vegetables like lettuce and any heavy foliage plants will appreciate fertilizer mixes with higher nitrogen levels.
•         Phosphorous promotes healthy roots as well as aids in flowering and fruiting. Thus you’ll want to use blends containing higher amounts of phosphorous when you’re transplanting, when the plant is establishing its roots and just before a flower blooms or a plant grows fruit.
•         Potassium promotes overall plant health, though it’s particularly useful for aiding strong roots and stems.  Certain root crops (like carrots) benefit from fertilizer mixes with a higher potassium content.