I have been using Rootrainers for years to grow overwintering onion sets, garlic and spring planted onion sets. Onion sets ( small immature onions) allow me to have onions all year round. Originally manufactured to grow tree seedlings, why would I use rootrainers for onion sets?
Growing onions from seeds can be a hit and miss affair, with weather, birds and the like all affecting the young seedlings’ growth outdoors, particularly those seedlings that have to overwinter. I am not after prize winning onions or even huge onions, reasons why people use onion seeds. I prefer sets. However, whenever I planted sets direct into the soil outdoors, within a few days, I would find many of the sets had been pulled up from where I had planted them and scattered all over the soil. Who or what was responsible?
Some detective work………Root Zones and rhizospheres..
When plants grow, the region of the soil around plant roots is called the root zone. The roots produce secretions that help and protect them as they force their way downwards through the soil. The immediate area around the root is called the rhizosphere. There will be many rhizospheres within the root zone of a plant. The rhizosphere is the most dynamic environment in the soil, or a microbe ‘hot spot’, the fast food areas of the soil! The roots are also continually shedding old tissue and sloughed-off plant cells. The root secretions and dead plant cells are food for microbes living in the soil. In return the soil microbes provide nutrients for the plants, which encourage plant growth. More plant growth means more roots. A win-win situation! Hence soil microbes themselves congregate around the roots. Microbes in turn are consumed by earthworms, who sense the root secretions and microbes in the soil and target such ‘hot spots’ to feast upon them!
Blackbirds deliberately pull up the onion sets to seek out earthworms and other such tasty morsels, living and feeding in the root zone underneath the onion set. Thus by planting onion sets in rootrainers, waiting for the roots to grow in and around the compost, binding it altogether, before planting them outdoors in the soil. Now unless the blackbird has fed on at least 3 Weetabix (!) that morning, it will not have the energy or strength to pull out the onion set and well rooted fibrous compost ball, which is a lot heavier than an onion set on its own. No more scattered onion sets!!
Onion sets are great for school kids! They are easy to handle, no fiddly seeds to sow, less skill is required when planting and together, sets and rootrainers make the exercise easy and interesting for children to do for themselves. One mayor advantage for schools is that the children can grow AND harvest them all within the school year.
If you would like more information on how to plant onion sets in rootrainers download here…..
Rootrainers available from http://www.haxnicks.co.uk/Garden/Rootrainers/
or telephone Haxnicks 0845 241 1555