Propagation Blog #2 Container Size and Medium
By LaVille Logan
I think it is essential to have a really good medium for cuttings. The ratio of soil, peat moss, perlite, vermiculite and worm castings is pretty critical to success. I have learned this though some massive failures. I researched online, and came up with a mix that I could make with what was available to me, using our ability to purchase materials at Redi-gro. My “recipe”:
Redi Gro potting soil – 3 parts
Perlite – 1 part
Worm castings -1/4 C. per gallon
Vermiculite – ½ part
My reasoning is that Redi Gro is a pretty good mix just as it is, and you will have success using it plain, so it is a good base. I add perlite to loosen the mix and keep it well draining. I add worm castings as a natural fertilizer which will not burn. It has microorganisms for healthy soil, and discourages root rot, aphids, mealy bugs and mites. I include vermiculite to increase water and nutrient retention. It is especially nice for water loving plants. I don’t measure very accurately. I have a plastic ½ gallon container which I use to dip ingredients from their respective bags.
I have been experimenting with straight perlite verses my mix when I do my cuttings, and it has been instructive. For instance, I used to root my abutilon trees in water before I planted them in mix and or perlite. I now know I get a much better rate of success planting them in mix immediately. I plant 4 cuttings close together in the middle of a 4” pot hoping for 2 or 3 to ‘catch’ and provide a nice, bushy plant. Surprise, I get 4 healthy stems about 95% of the time.
Other cuttings I start in an 8oz. clear plastic cup (I have drilled a quarter in hole in the bottom, I can drill several at a time without them flying all over) I use clear cups so I can see the rate of rooting and know when it is ready without having to knock it out of the pot. Label the plant with name and date it was done. When repotting to the next size up, either a 4” pot or a 16” plastic cup, I use a dusting of Sure Start before placing cutting in larger container. This may be the last size I use for sale, but for large plants–trees, hydrangea, fast growing marguerites—I repot again to a gallon pot. Each time, I cross out the previous date of potting on the label, write the new date, and keep it with the plant.
When I repot something planted initially in straight perlite, I gently rinse the perlite off the roots, back into my barrel of mix, then plant the cutting (still holding on to some perlite with its roots) into a larger container, don’t forget the Sure Start. Water to settle the mix and do not press down. Perlite is a good rooting medium for many plants, but contains no nutrients, hence the need to watch roots and repot in a timely manner.