SMOKE TREATMENT FOR SOME SEEDS FROM AUSTRALIA.
I wondered what I could write about and then I had two enquiries about using smoke treatment for seeds, so I thought a rundown on the subject might be interesting.
Some Australian and South African plants live in areas that experience severe bushfires and have developed a strategy for survival despite the fire. Seeds of these plants are shed and remain dormant in the soil until their germination is triggered by smoke.
How it works is this. A bushfire occurs and the whole area is bathed in smoke which carries chemicals that were in the burnt material. The chemicals coat everything the smoke envelops. Rain follows the bushfire and washes the chemicals off everything and into the soil where it coats the dormant seed. This one event tells the seed that the bushfire season has passed and seedlings will be safe and the water provides the moisture needed for germination. Seeds outside the burnt area but covered by the smoke will also germinate, those outside the smoked area will remain dormant.
So, how do you smoke the seed without lighting a bushfire in your backyard? There are several methods, some very expensive and some not. You can purchase a smoke impregnated paper and place it on the top of the pot or seedling tray (one time use & expensive) or you can purchase smoke impregnated vermiculite. Vermiculite is a mineral that is superheated so it pops much like popcorn. The result is small silvery flakes that are inert, that is it doesn’t contain any plant nutrient and it is used to open up soils and retain water.
Smoke is bubbled through water catching the chemicals and applied to the vermiculite which is then dried. Sprinkled on top of a pot or tray and watered in, the water washes the chemicals out of the vermiculite and over the seeds. (medium cost).
If you take a small jar put a teaspoon of smoked vermiculite in it and cover it with water. Shake and let stand a few hours then shake again. Put a little of the water into the lid of the jar and drop the seeds into it. Soak for an hour or so then sow the seeds as normal. Pour the water back into the jar and use again. (very cheap)
Smoked vermiculite is available in my store – www.olelantanaseeds.com.au
Seeds requiring Smoke Treatment include Geraldton Wax, Kangaroo Paw, Boronia, Chocolate Lily, Mountain Blue Berry, Heath plants and Erica.