radish radish everywhere...

Wow, there is a lot of radish out there!

It is especially noticeable with it's bright yellow colour now that it has been either sprayed down or frosted. Currently, there are two main types of radishes being grown as cover crops in Ontario. Below is a comparison of the roots:

Tillage radish tends to grow a tap root straight down without any fibrous roots branching out. Oilseed radish can grow a more rounded tap root with a few more fibrous roots. There are claims that both forms can break up compaction and add to soil health.

For me, the jury is still out on Radishes. Here's why:

-I'm all for adding organic matter to the soil but am not so sure that radishes are any better than a cover crop of clover. I need to see some more research on it.

-One of the first lesson that I learned in science was that "matter can not be created or destroyed". Planting radishes is not going to magically increase your soil fertility if you are not adding any commercial fertilizers or manure. Radishes do not fixate atmospheric nitrogen like clover does. They will trap nutrients from manure applications for future crops but the availability of those nutrients is dependant on the rate of breakdown of the radishes.

-the price of seed is still a major restriction for use.

-radishes are not the silver bullet for compaction. Yes adding organic matter to the soil will help but think about how the root of the tillage radish grows. Rather than compacting the soil vertically, the root is spreading the soil sideways creating horizontal compaction, almost like driving a post into the ground. The best solution for compaction is a fibrous root system that works it's way through the compaction in many small channels rather than one big one.

-one last point. Remember, those big tap roots need to break down in the field to do the soil any good and when they breakdown they rot... and stink.... if you do use them, don't plant them too close to your home or your neighbours!