Wedge cuttings are the easiest way to start many plants at a time with the least plant material.
It’s especially useful for rare begonias or begonias that only have a couple good leaves to use.
In the illustration you can see how to cut a leaf into wedges.
A wedge is simply a portion of leaf with a vein in it. You can make your wedges as small or as large as you like. Smaller wedges may not survive if your conditions are less than perfect. I usually make my wedges about an inch or inch and a half long. For wedges, conditions must be as sterile as possible.
As stated earlier in this chapter, a razor blade is the best utensil to use for cutting. Perlite is the best medium for rooting wedges. Add a very slight amount of fertilizer so the plantlets have some food when they start to grow. You can fill a tray with perlite and premoisten. When perlite is wet it becomes very solid.
I use a knife or plant label to make rows of small slits in the perlite the right size to fit my wedges. The wedges can be touching or overlapping so don’t be afraid to pack them closely. Usually about half an inch to and inch apart works well.
Try to insert the wedge as upright as possible. Also make sure to label carefully and keep different varieties separated. Try to mix the tray up so that varieties that aren’t a similar color aren’t next to each other so they don’t get confused later. They do require a covered container.
Wedges may take a couple months to form roots and plantlets. Check the moisture of the medium regularly to make sure it doesn’t dry out. Misting occasionally with a weak fertilizer for foliar feeding will help them along. You may want to leave the cover opened slightly till they dry off a little before closing tightly.
Using distilled water will make sure that you don’t introduce any diseases into your sterile environment.
As soon as little plantlets have come up and are large enough to handle they can be potted up individually into small pots.
The illustration (on the right) shows the new plantlets coming up from a leaf cutting and wedge cutting.
For the first transplant they should remain in a covered container. Treat them as you would seedlings of the same size.
Once they have filled the small pot and are ready to transplant again, you can harden them off and move to other locations.
Credits / references:
Brad Thompson | Brad’s Begonia World