Mulching yacon and oca

This past season I decided to experiment with mulching some of my oca and yacon beds to see what the differences would be.
I mulched two beds of each, left two beds unmulched as I usually grow them, and grew two beds in the open with no mulch or shadecloth. Note that in my Australian scorching summers I have to use 50% shadecloth row covers on most of my vegetables.

Yacon: There was almost no difference in production of the mulched and unmulched beds. The only difference was a very slight reduction in the amount of edible tubers in the mulched beds but it was not very significant. I did find that the plants in the mulched beds started to shoot weeks after the unmulched beds, I even overplanted one bed with melons as I thought they had rotted. The melons grew quite happily among the yacon. Basically there is no advantage in mulching yacon.

Oca: The oca in the mulched beds also started growing weeks after the unmulched beds, because of the stable temperature I imagine. There was a huge difference in the health and productivity though with the mulched beds having much healthier plants and almost no sign of stem rot which is a problem with oca here caused by heat. There was a marked rise in the ratio of eating size tubers (over 5cm) to small tubers in the mulched beds. I will certainly be mulching from now on.
I haven’t mulched oca up till now and thought that I would lose a lot of tubers due to mice and slugs but although I saw many slugs there was little slug damage, and I saw no mice in the straw. I think there would normally be more mouse damage but this year there wasn’t many to be seen.

All the plants in the uncovered rows did very badly with nearly all the oca dying and the yacon growing very small and producing very few eating size tubers.

This is very interesting, Rowan! Thanks for posting.

You are in a good spot to test for growing oca in hot conditions, so I am encouraged by your results. Mulching sounds like a very good idea for warmer areas. I usually don’t have problems with slugs (not because we don’t have lots of slugs, but because they aren’t much interested in oca), but mice/voles are a big problem and they make me very uneasy about mulching anything.

Are your summers dry or humid? I wonder if the mulch helps more by regulating soil moisture or temperature.

My summers are very dry. I am guessing that it is the temperature regulation that has made the mulched plants growing better as I water regularly so they don’t tend to go through dry/wet cycles. I also think that the mulch holds the water enough to create more of a humid atmosphere around the plants than just the soil which dries out on top in the heat. I will be experimenting with a couple of different mulch types next season.

I did have problems with mice (I am so glad we don’t have any of your other mammalian pests over here) last year which is why I was a bit concerned with the straw but for some reason there weren’t many mice around this year. It might be very different next year, but it is always a good learning experience.

This problem of voles and mice creating havoc under mulch (or even without mulch) is something that many of us share. Like Rowan, my summers are hot. As I gain experience growing oca. I am becoming aware that mulch may be a good idea. However, I am thinking that it might be best to be accompanied by a plan to deal with the rodents as well.

Over the last couple of years I experimented with a simple application on my beets and potatoes that seems to work. It involves scented castor oil. On a small scale, you can use a watering can and add 1 teaspoon of castor oil, 1 teaspoon of dish detergent, and then fill with water. The key is to soak the soil, not the plant. It is organic so no risk to you or your plants and only needs to be done once a year. Since doing this I have had zero damage from either voles or moles. I will be growing yacon for the first time this year so will be doing the same for it.

If you want to see more detail, have a look at the following link: Apparently this fellow solved what was a major problem in his hosta business.

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