Main Oca Bed 2011 — If It Ain't Broke...

Last year's growing arrangement of Oca with cordon tomatoes was hard to fault, so I've just tweaked it slightly to optimise spacing and make it easier to manage this time round. Oh, and it's beetroot instead of lettuce for the quick-growing edge crop.

Here is Oca 'Dark pink', not yet at the sprawling stage, growing strongly between tomato 'OSU Blue', despite being subject to a medley of drought, high wind, downpours and hailstorms since planting out.

26/6/11

Observant readers might notice that there is incomplete fruit set on the tomato. I'm pretty sure this is due to the very dry conditions earlier in the season rather than any affect from the oca foliage covering the lower trusses.

The bed's timetable in detail:-

13th April. Cleared the preceding green manure crop (grazing rye). Tops hoed off with an azada, and removed, roots left in situ. Not dug.

14th April. Beetroot (plugs, sown 15th March) were planted out.
The tiny plants are just visible in rows 9" from the bed edge (centre foreground bed)...

I could have planted out the Oca at the same time, but last year they got a bit of frost damage around now, so no need to rush things as they are happily growing away in Root trainers at this point.

9th May. Oca and tomatoes finally get planted out. The Root trainer method seems like a success, and I'm sure this will give them a better start than using pots.

Tomatoes planted, Oca laid ready to plant, beetroot doing well...

That's Cheltenham Greentop on the left, and 'White' on the right.

The tomato supports are on 16" spacing, with 24" between the staggered rows. Incidentally this assumes using the UK conventional cordon growing method (side-shooting, and deleafing lower part of stem). If you use the American cage method I'd go for much wider spacing.

5th June. Full ground cover from the  Oca between the tomatoes, and beet down the edges (beetroot now being harvested).

10th June. Tomatoes are starting to crop. (Below) This is Katja, a Siberian variety, surprisingly the first to ripen. Thanks to Søren of Toad's Garden for the seed.

31st June. Oca stems over-reach themselves and collapse down at this time of year. This, along with deleafing the lower part of the tomato cordons improves ventilation and light access. The dappled shade from the tomatoes is enjoyed by the Oca, reducing stress in hot weather.

8th August. Tomatoes in full production.

1st October. Tomatoes on the wane, Oca ascendance.

4th December, tomatoes removed after the first light frost.

Tubers are swelling!

Harvest still to come!

High Summer Miscellanea

A few things of interest that caught my eye while patrolling the plot the other day:

Tomato, De Barao Black (thanks Toad) with Oca growing at its feet. It's my first year with this variety, and it's turning out to be very productive - the canes are buckling under the load. The taste is slightly lacking in acidity, but it's good for cooking. I'll be saving seed and probably adding it to my 'grow every year' list.

That's Tigerella (also known as Mr Stripey) with Oca, as usual, providing ground cover. I've already demonstrated that tomatoes and Oca grow well as a bi-crop, and it's working just as well for me again this year.

The first of this year's Yacon flowers with a hoverfly getting stuck in. I'll be watching for seed setting, but like Oca, this is another awkward outbreeding blighter when it comes to pollination - this time because male flowers don't appear until after the female flowers, and even then, seed set is said to be poor.

A domestic bee and a bumblebee doing their thing on a globe artichoke. The plot is literally buzzing with pollinators this Summer. This is partly because we have beekeeping on the site now, but also the increased use of organic methods by plot-holders seems to have boosted the general insect population. This is all good news, especially for those of us aiming to collect seed from difficult-to-pollinate crops like Oca or Yacon.

This is Ulluco, which I'm growing for the first time this year. Having now seen its growth habit, it seems another strong candidate for ground-cover in a vegetable polyculture. It's lower-growing than Oca, and fills out as ground cover a bit earlier in the season. I could see it working well with leeks, corn, chili-peppers, tall peas, tomatoes...
But first, I need to obtain tubers from this year's crop, which is by no means guaranteed from all accounts.
Update: Harvest results here.

Other gardeners have squashes growing out of their compost heaps ...
Hats off to Oca, a resilient survivor - last year's dross tubers have sent stems struggling through the 3mm wide aeration holes of this plastic compost bin despite being buried under two feet of mouldering vegetable peelings.

Oca Crossing - Giving it a Stab

The threat of frost has finally gone, and space is needed in the greenhouse for expanding tomato plants, so the Oca must go out into the ground.
With multiple varieties at hand this year, there is the obvious opportunity to encourage some crossing with the hope of selecting for reduced day-length sensitivity. It's new ground for me, but armed with a recently purchased copy of Carol Deppe's 'Breed Your Own Vegetable Varieties', and having learned of the picky outbreeding ways of Oca on the Radix website, I feel ready to give it a go.
My limited stock of new varieties needs to be multiplied up for a planned variety trial next year, so this year they can be grown mixed closely together in one bed to maximise the opportunity for natural and assisted cross-fertilisation. Lets just hope there will be some simultaneous multi-variety flowering, and bees that know about Oca stylar morphs! Otherwise it's going to be knee-pads, tweezers and magnifying glass.

(Below) Here they are laid out for planting. I'm using a slightly denser pattern than previously - two staggered rows of Oca down the centre of the bed.

The bed still has to earn its keep, so once the warm weather arrives cordon tomatoes are added either side, and a quick row of plug-grown red lettuce seedlings along each edge makes full use of the space.
I had a bag of builders sand lying around, so I've scattered it on the surface to reflect light up to the toms, which have been suffering in an overcrowded greenhouse for too long. Here's the view on 21/5/10:




There is a very brief flurry of flowers from one variety in early June (see 'Early Sprouter, Early Flowerer'), then nothing until the 19th of September when one of the variety 'White' produces a flower or two. Conditions were obviously then right, because all of the 'White' plants started to bloom wholesale.

Up until very recently it has been generally accepted that a single Oca variety cannot self-pollinate, but leading-edge events seem to undermine this belief.
Taking this in to account, even though I have only one variety in flower at this stage, I think it is worth the effort to bag a few of the flowers just in case I can collect some seed.

Bagging is required because Oca has a very effective seed dispersal strategy - exploding seed pods.
There's been heavy rain and strong winds, so I've tethered the bags to wire pegs to make sure I can retrieve them all.

Despite the change in the weather, there still seem to be plenty of pollinators at work, so no need for manual methods yet. I watched this chap systematically visiting every Oca flower along the bed before he headed off towards some squash flowers.

30/9/10 The really good news is that I can see flowers buds developing on three more varieties : pale pink/purple eyes,
gold/purple eyes, and white/pink eyes.
Another week, and I'll have potential for some crossing action!
Now, if it would just stop raining ...

20/10/10 Drat! Frost kills all plants. No ripe seed obtained.

2009 Growing Season - Oca with tomatoes

After some consideration I decided to bi-crop with tomatoes as the primary crop.

So ... Action-points for this season:

• Use a more formal multi-crop structure.
• Allow more space for the ultimate size of the foliage.
• Hold out for as late a harvest date as possible.
• Keep better records of dates, spacing etc.

Early March. As previously, I chitted tubers indoors.

Although the tubers saved from the previous season are technically genetic clones, I noticed one tuber sprouted much earlier than the others. Another was a much darker colour. Some mutation does occur, so I have labelled them and will see if the characteristics are passed on.

25th March, planted in pots in an unheated greenhouse.

28th April. Planting out. The plants will be placed in a single row down the centre of a 4ft wide bed (hopefuly giving enough space for the Autumn spread) alternating with the primary crop of cordon grown tomatoes. Spacing is about 20 inches between each tomato, with an Oca between each. Space on either side will be used for spring-sown, fast-maturing crops, which will be harvested before the space is taken by the Oca.

The bed has had an early (sown in February under plastic) green manure crop of mustard. Without disturbing this, 7ft canes are placed ready for the tomatoes, and ...

...the Oca are transplanted in small clearings giving them some protection from any cold wind.

By 9th June, the mustard is long gone and the interplanted tomatoes are knee-high. Direct-sown salad crops are up (here, landcress and spring onions, not visible are module-sown beetroot and lettuce) The tomatoes have received a layer of mulch to encourage stem-rooting and the Oca is still well-behaved.

By 1st August the fast-growing side crops are mostly harvested, just in time for the Oca to spread dramatically.

I was concerned that the lower trusses would be slow to ripen due to shading from the Oca, but they seemed no different from those in the control bed (without interplanted Oca).

17th August. Tomato cropping is in full flow. The single row of oca is providing complete ground cover across the 4ft bed. The tomatoes have been stripped of leaves over their lower third to aid ripening and ventilation. This also lets in more light to the oca.

1st of November. Blight and cold weather have just about finished off the tomatoes. The Oca is thriving in the cool temperatures and increased moisture levels.

Its' happy enough to flower..

.... and show the first signs of tuber formation. Stems in contact with the ground produce thick fleshy roots which form a tuber at the end.

(6th December) A light frost has damaged the outermost foliage. This seems to have stimulated tuber formation. There are huge numbers of tubers forming where the stems are touching the soil.

(20th December) Two weeks later there have been several proper frosty nights. The crucial period for tuber growth is now!

The plant guild offers up an unexpected bonus crop; the Spring-sown land cress has survived the hot Summer under the Oca, and is now making a come-back through the collapsed stems.

31st December. The foliage is well and truly dead. Surely time to harvest!

For harvest results go here