Oca/Corn/Huauzontle Polyculture — Still Seeking Low-Work Resilient Growing Systems.

In 2010 I posted here on interplanting Oca and sweetcorn. This year, I'm going a stage further by adding Huauzontle (or 'Aztec Broccoli') to that system. Huauzontle is a Chenopod crop producing greens and edible flower-shoots, historically an encouraged weed or tolerated volunteer in Central American maize fields.
Here are the three constituent crops ready to plant out on the 16th of June, Huauzontle on the left...

The Huauzontle seed came from Real Seeds, and was ridiculously fast to germinate; the seedlings were up in 48 hrs, so in future, I would direct sow with confidence. But this time they were multi-sown in cells a week or so after the corn.
The maize is Painted Mountain obtained in a seed swap parcel a few years back, (thank you Jayb). It gave 100% germination despite its age, in sowing conditions that were not really warm enough by normal standards. It's a many-coloured genetically diverse, heat and cold-resilient variety, bred to thrive in the Rocky Mountains. After last year's weather, I'm seeking resilient varieties! Two trays of commercial sweetcorn sown on the same day all rotted, thanks probably to chilly nights in the greenhouse. Not chilly by Rocky Mountain standards evidently.

The oca are a motly collection of leftovers stunted from being left in small cells too long.

Here's the scheme on planting day. That's a four foot wide bed...

 ...which has just been newly created by double digging, incorporating all available organic matter to full depth. Carrying through the resilience theme to the soil, there are even logs buried under there; anything to build up this silt soil, and give some water holding capacity.

Just four weeks after planting, quite remarkably the huauzontle was already providing greens and seed shoots for steaming, but proving too vigorous for this scheme, or at least is too thickly planted, and is shown here just before receiving a serious cutting back...

A few spare lettuce were squeezed along the edge too, and the paths mulched to limit water loss during the ensuing heatwave.

By the beginning of September the corn is ready to pick...

...and, despite occasional chopping back, the Huauzontle continued to be a bit too resilient. The Oca are definitely suffering from lack of light and water at this stage.

Here is the view of the bed on 31st October...

...The oca are expanding fast, fighting back, and flowering, with every indication of a decent harvest to be had by mid winter. The Huauzontle, disheveled by recent gale-force winds, has turned spectacularly red and carries a massive seed crop, so it seems likely that I, just like Central American peasants, will have it as a tolerated volunteer in seasons to come.
With wider spacing of the Huauzontle, this scheme would approach my ideal; no weeds had a chance, and the bed yielded well, but required almost no work input once created. And like the Forth railway bridge, it has redundancy — bits can fall off it, but it still works.

Oca / Sweetcorn Bicrop

Various sources state that this is a traditional Andean cultural method, but I cannot find any description of the specific planting patterns used.  They may well have used alternate widely-spaced rows of earthed-up Oca with later-planted corn. But I think corn pollination might suffer from the wide spacing, and the unnecessary soil disturbance and labour does not appeal to me.
I want a method that will suit my no-dig 4ft wide beds, and I think block-planted corn with oca near the centre-line of the bed is going to be the most practical approach for me.

Back on the 25th April the preceding crop of grazing rye was hoed off and removed (for strawing strawberries). Small pot-grown Oca were planted out on the same day.

By the 17th May (below) the Oca are established, but looking very lonely. I never like to see bare soil at the best of times, but continuing cool weather has meant the delayed planting of corn, and the Oca have been on their own for longer than expected. I should have left some of the grazing rye crop-debris on the surface to shade my precious humus and reduce surface evaporation.

Spacing for the corn is the tricky bit. I have a theory that if I can get the corn to support the Oca in an upright position, reducing stem contact with the ground, and thus reducing stem tuber formation, the plants will  be forced to concentrate all of their energy into bigger tubers around the roots (see Tubers- big and few, or small and many), and Oca - Be Erect not Supine!). The corn will have to be reasonably close-planted to do this, but must be far enough apart to admit light to the Oca - a fine balance.

6th of June, the sweetcorn are ready to go...

...and are spaced on a grid of about 1ft across the bed and slightly more along the bed. The Oca sit on the same grid so that each is surrounded by four corn. Just visible are beetroot plugs added along the edges of the bed to complete a three-way polyculture, and utilise the extra light available at the sides.

Plants watered in, paths mulched, there should be no more work until harvest.

Just one week later (13th June), all three crops are putting on amazingly fast growth. Notice the unusually early Oca flower. 

By the 20th of June, just 14 days after planting the corn, the canopy is about to close. So far, the spacing seems to be working just right, and the weeds won't get a look in.

4th July (4 weeks after planting corn) Stand well back everyone!

Keeping a log with photos and dates really highlights how quickly crops grow in midsummer. The Cylindra beetroot are already of a useable size, the corn is waist high, and the Oca foliage is relentlessly advancing towards the edges of the bed.
We've had consistently hot sunny conditions for the last few weeks, and I think the Oca is probably benefiting from the partial shading of the corn.

23rd July. The corn is above head height and showing signs of flowering. Some beetroot have already been harvested, and the Oca is giving full ground cover to the bed.
Weed suppression is absolute.
With the continuing drought, I've been forced to water a few times, and strong winds flattened some of the corn, so they have been staked, but otherwise the bed has looked after itself just fine.



20th August. The corn is cropping. It's averaging two good-sized cobs per plant, so six per linear foot of bed. The beetroot have all been eaten.

14th September. The corn has all been harvested, and the plants cut back to admit more light to the Oca during the shortening days.

Update, 2010 Oca harvest here.