Last month we discussed the important role of having good air flow and ventilation in your growing spaces. It only makes sense then that our plant tip for May is all about making sure the roots of your plants are also getting enough air. Many of the most collected plants prefer a well aerated, or fast draining soil mix for their root systems. For these species, plant health suffers when the plant is grown in a soil or media that is too dense to allow air to pass through, or retains too much moisture for extended periods of time. When I am asked what is wrong with a plant, the cause is most often some combination of overwatering and /or soil that does not adequate drainage. In fact, many experienced growers prefer growing In ways that provide a lot of aeration to the roots, so let’s go through some tips and tricks that we have seen work effectively.
Use a potting mix that includes generous amounts of fast draining materials such as perlite, vermiculite, orchid bark, gravel, pumice, or similar materials. You may also consider growing plants in leca (clay pebbles), perlite, sphagnum moss, or pumice. These media allow water to pass through your potting mix very quickly, and only hold onto a small amount of moisture so that your plants are not left sitting for extended periods with ‘wet feet’. These media also tend to work well for bottom watering your plants, which can be another way to reduce the chance of overwatering your plants.
Use pots that have an adequate size drainage hole and that are made of materials that are air permeable - A hole at the bottom of the pot will ensure that excess water drains out of the pot. Otherwise water will pool at the bottom of the pot and your roots will be left sitting in overly moist, mucky soil. Terracotta and fabric pots are great choices for growing because they allow air flow through the sides of the pot. This provides a lot of air to the roots and allows the soil to dry out more quickly.
You can go even further by growing in net pots, which are plastic pots that have a lot of small holes so that the potting media stays in the pot, water drains through quickly, and air can more easily get to the soil and plant root zone. Also, it’s important not to let your plants sit in a tray of standing water. If there is excess water in the bottom tray, dump it out.
Water only when the soil has had a chance to at least partially dry – Check how frequently you need to water each species of plant. There are some plants (i.e. calatheas) that prefer the soil to be slightly and evenly moist, while many species (i.e. many aroids) prefer to be watered only after the first few centimetres of the soil dries out. For most houseplants, you want the soil to at least partially dry between waterings so that air can get to the root system.
All the factors above lead to water passing through the soil more quickly, soil that remains light and does not become overly saturated, and soil that dries out more quickly. These in turn lead to more air reaching the roots more frequently. Trust us, we have tried all these tricks out with immediate and noticeable success with a variety of plants including philodendrons, anthuriums, syngoniums, cactus, succulents, and just about every other plant you can imagine.
Plant Revolution Costa Rica