That beautiful dendrobium orchid has just finished blooming, and you notice it needs re-potted. The roots are tight, and the plant looks much too large for the current container. Now you can go and buy a bag of pre-made orchid mix at a supply store, or you can make your own soil. The first option is the easiest pick, but making your own soil gives the gardener greater control.
Making your own potting soil is fun and presents a new challenge for the gardener. It is especially useful when your plant collection becomes quite large. It is more cost effective to buy a bag of orchid mix when there are only a handful of plants that need re-potted, but if you have a collection of eighty orchids with twenty that will need re-potted there are usually savings in making your own. The benefit is that you can buy in bulk.
Look at what mediums are in the current flowerpot and use those ingredients as the starting point for your homemade mixture. Orchids, for example, do not like to be wet so they need a fast-draining medium like lava rock or coconut husk chips. If you buy an orchid at a chain store they are typically potted in only moss and Styrofoam peanuts, so I always repot the orchid into a mix that drains quicker than moss. A handful of charcoal is often recommended for “sweetness,” which acts like a dessert for an orchid.
After the orchid is re-potted you then notice the tangerine tree could use a larger container too. You can take the leftover coconut chips from the orchids and use that as a base mixture for the citrus tree. Homemade compost or store-bought potting mix is easily combined with the coconut chips. I mix in a little charcoal and add both vermiculite and perlite for water control. The citrus trees in my greenhouse always seem plagued by mealy bugs or scale. To help combat these pests a granular insecticide is added to each batch of fresh potting soil. Depending on the tree type a scoop or two of dry citrus fertilizer can also be added into the mix.
Citrus trees have the most complex soil in my greenhouses, but simple plants like geraniums grow quickly and need re-potted each year. General house plants receive a mixture of potting soil, dry garden manure and insecticide. After concocting your mixture, in a bucket or potting bench, take a big spoon and stir all the ingredients together like you would a soup. Take mental, or physical, notes of how the plants respond to your homemade soil. This will allow you to improve for the next round of plants that need re-potted.
Keep in mind you will need space to store your potting soil mixtures. There will probably be 2-3 bags of materials which need to be always stored as you will normally have left over ingredients. Bags of charcoal are small, but potting soil bags are usually quite sizeable and take up floor space. Coconut husk chips start packaged at the size of a sandwich baggie and can also be bought in large boxes. The bags can be stacked on the floors, placed in a container, or be placed on shelves.
Always research the potting mediums of a particular species before transplanting. Online garden forums are an excellent source of information, and there are also many books available through libraries and friends so do some research and give it a try. Most garden stores from specialty shops to big box chains have the basic ingredients. Plant festivals are another great place to find soil ingredients and of course you can order anything online. I have yet to kill a plant from bad potting soil so don’t be afraid to try it. The fresh soil will be a joy to your plants.
Lyndsey Roth is an experienced greenhouse gardener and frequent My Garden & Greenhouse contributor.