Growing Kumara/Sweet potato in a wet climate

[Mike1994]

Hi All,

I am new here and live in NZ, I grow most my veges and now I'm trying to grow kumara/sweet potato, I live in land from Greymouth on the wet West Coast of the South Island. I have been watching Self Sufficient Me on YouTube for a while now and am wondering if any one has any thoughts for growing sweet potatoes in a wet climate. We have been told its to cold and wet to grow them were we are. But we tried any way, we used black plastic last year and got an alright crop. This year I have made two raised beds about 400 mm high and about 15 m2 each, I filled them about 2/3 rds full with bark and compost and filled the rest up with straw from calf shed bedding. Now to my main question, should I still use plastic to combat our annual 3 meter rainfall or will the raised beds do the job, I rotary hoed the clay under the beds down about 200 mm to help with drainage. What are you thoughts.

Mike

 

[Mandy Onderwater]

Welcome to the forum @Mike1994 !

Sweet potatoes tend to prefer sub-tropical to tropical climates. It does not necessarily mean they won't grow in other climates, thought they may not thrive as well and may require special care.
I'm no expert as I haven't grown sweet potato myself, but I believe sweet potatoes thrive in temperatures between 25 and 35 degrees Celcius. They may suffer damage and/or die in temperatures below 10 C. It may endure a short time in colder temperatures, but when it reaches freezing temperatures the plant will most likely die.
A way of combatting this is by ensuring soil temperatures stay high, by insulating the soil/garden beds. Black plastic covering your soil can also help in raising soil temperatures as it attracts more heat. Soil temperature really shouldn't be below 15 C and preventative measures might need to be taken - or you can grow the plant indoors!

Thankfully there are many "normal" potatoes that can thrive in colder climates, which may be more suited to your situation.

 

[Mike1994]

Thanks Mandy,

I don't think temp will be a problem as we do well with corn, potatoes, squash and in the summer we can get up to 28 degrees C and because of our high rain fall (3 weeks without rain in summer is a drought) the air is very clean so the sun is very intense compared to other parts of the country. My main concern is the wet, will I need to use plastic in my raised beds as was done last year on the strait ground. In my research not using plastic seems to produce a bigger crop (as Mark said in his 5 tips to grow a ton of sweet potato) but if its too wet will I get rot. The variety I believe I have got is Beauregard.

Mike

 

[JP 1983]

They grow sweet potato across Korea in the summer, although mostly in the south where it is warmer. It rains a lot there in summer though, but not quite your 3,000mm!! I think using the plastic is a good idea to halt potential rot in the tubers, but if you're trying to avoid the expense you could run an experiment like Mark does. Have one bed use the plastic and the other without, and see which one gives you the better crop and use that method again for both beds next year.

 

[Mike1994]

Thanks JP, not bad idea will try. Just to clarify we don't get 3000mm in summer that is our yearly rainfall so most of it is on ether side of summer. Does any one know what rainfall sweet potato can handle I couldn't find any thing on line. We stared red pineapple last year and they are meant to handle up to 3000mm and they did alright if I protected them from the frost.

 

[Mike1994]

I should also mention that yam grow like weeds here with no help at all, is sweet potato more prone to rot than yams?

 

[JP 1983]

I should also mention that yam grow like weeds here with no help at all, is sweet potato more prone to rot than yams?

I think yams have a thicker tuber skin than sweet potato, making them very resistant to rot. They're super easy to grow and survive well even in the wet tropics (esp. northern Aus). Why not grow those instead?

 

[Mandy Onderwater]

I'm seconding what @JP 1983 has said.

I'm not sure how much "wetness" sweet potatoes can handle. I know most plants can handle quite a bit, provided the soil is free draining. But the exact sciences I do not know regarding this, sadly.

 

[Mike1994]

Thank guys, I have been growing yams for about 5 - 6 years now. My soil is reasonably free draining and in the raised bed its a lot better, so I will try you ideas and see if the sweet potatoes do better this year in raised beds than last year's strait in the ground

 

[Mandy Onderwater]

Let us know how you go! I'd be very interested

 

[JP 1983]

Yeah pics pls. Both of yams and kumara. Cheers!

 

[Briztank]

@Mike1994 is it kumera and yam planting time in NZ at the moment? I've whacked in the spuds but would be keen to get yams and kumera going too if it's time. Are kumera and yams happy with a bit of shade or better in full sun?

 

[Mike1994]

Both like as much sun as they can get, one thing with yams and I believe its the same with kumera is don't use nitrogen, all you will get is leaf. We had our last frost this week so I will be planting out soon with my kumera slips, with the yam just put some small ones in the ground and they will sprout or better still find some that have already started sprouting. I found a bucket of yams from last season that we dug up about 6 weeks ago and forgot about them and they had started to sprout

 

[Mike1994]

Yam should be able to go in the ground were we are (and we are right beside the alps) now even if we get another freak frost they will be fine if they are still under the ground