Page 18 - Simply Veg 1 2024

Coir Potato Harvest
Back in the April 2023 edition of the SV magazine, we wrote about trialling potatoes grown in coir.
As a reminder, we used Coco & Coir “CocoGrow” compost which was on offer in our local Morrison’s supermarket, and “Emily” potatoes, a new variety to us, which were kindly gifted to us by
one of our DA members.
During the season, we watered the potatoes to keep the coir moist. As we had been advised, we did tend to find that coir seemed to dry out quite quickly compared to other compost we’ve been used to, so we took a “little and often” approach to watering. We also fed the potatoes with a
high nitrogen liquid feed whilst the haulms were growing, which we hoped supplemented the slow- release fertiliser that we’d added to the coir in the first place.
Given we were only trying a few tubers, we treated them all the same. Looking back, we probably should’ve had a
“control” pot, and then treated each of the others slightly differently – one to consider for next year maybe! As coir is totally new to us, it would definitely be worth trying different things with it to see what makes a difference (or not as the case may be!) We
could do with understanding more about: (i) amount of base fertiliser that proves useful, without being wasteful; (ii) how much and often to water to get the best results; and (iii) any supplementary feeding required. Answers on a postcard please if any of you have experience! Of course, this will all also differ between crops as well
as for the same crop at different points in its growing season. In any case, lots more to be thinking about in future years as we keep learning about coir.
And now for the results!
One of the pots didn’t do too well. The haulms died back quite early on and so we harvested this one earlier than all the other pots as we thought it may have some kind of disease. Luckily it didn’t, so not sure why it died back so early, and when we tipped it out, we still got a decent crop from the two tubers. It’s just some of the tubers had not fully developed yet. There were lots on the root, but many of them were still quite small. They still tasted just as nice though!
We left the other four pots until the haulms have completely died back, and then cut these off and let the potatoes stand in their pots for a couple of weeks to dry out. When we harvested them, these were the results:
• Pot1:846g
• Pot2:918g
• Pot3:1,205g
• Pot4:1,654g
The crop wasn’t as big as we’d hoped, but we’ve still got some potatoes to keep us going through the winter. When we tipped out the pots, one of the tubers from each pot had seemed to have rotted off, as there were lots of little tubers in the pot that had rotted away after initially forming. Not sure what caused that but suggests that the crop could’ve been double what it was if all the tubers had survived.
Overall the tubers weren’t very large, there were lots of “marbles”. However, we’ll eat them anyway! The largest tuber we got was 256g, and there were a handful this sort of size across the four pots.
I think our growing position wasn’t ideal for them. It was sheltered, but up against
After chitting, we
removed all the shoots
except one, leaving
the strongest one on
each tuber intact when
planting. We added 8oz of
slow-release fertiliser to
75 litres of coir when we
made it up and planted
two tubers per 30 litre
pot. We filled the bottom of each pot with a couple of inches of compost and then placed the tubers in and covered with a couple of inches of coir. As they began poking through, we gradually topped the pots up until they were full.
lots more to be
thinking about in future years as we keep learning about coir
18 Simply Vegetables
EMILY HARRIS