So its been a crazy month – I’ve missed you all! We’ve harvested over 1000#’s of potatoes -and sold them- hitting farmers markets for the first time. There is at least another post of stories there, but for now suffice it to say we love that we have become “the Potato People” in at least two towns and that feels great.
With the farm gardens under control again, I spent a beautiful half hour this weekend working through the Straw Mulch Potatoes that I had put in as a test of deep mulched potatoes (no updates on the towers yet – 2 of the three are still growing and the third blighted so bad I only got 3 spuds for 4 seeds planted). The Straw Mulch bed had 10 plants, and had been sheet mulched with 3″ of horse manure a year ago, and then got another foot of straw thrown on top as the potato plants grew. No additional fertilizer, no sprays, and not much irrigation was provided (an inconsequential 10 gallons total from washing out compost buckets). My hypothesis was that the rich, untilled soil from the sheet mulching combined with the more constant soil moisture provided by the deep straw mulch would help tuber size and plant vigor. On top of that I was very curious to see if there was any credibility to the claims of increased tuber set from the deep mulch, and how the harvest labor would compare.
First off, I am very pleased with the yield and am convinced (as much as one can be after one test) that super rich soil and deep mulching equates to better yeilds. Here is my proof:
30#'s of spuds from 10 plants!!!
With an average yield of 3#’s per plant I would be getting 270#’s per row at the farm – a 50% improvement over my current technique – and I was already getting a solid 8.5:1 harvest ratio! I planted this bed with 4 medium sized Purple Vikings – just under 2#’s. Yes you got that right – a 15:1 ratio which is near record yields for even conventional farmers.
To put that another way if I can scale this technique up and apply it to my current spacing (3′ rows, 14″ spacing) I could get 43,500#’s per acre which equates to 18,600,000 million calories. With the blight coming in growth was stunted and overall tuber size was down compared to what I expect from Purple Viking. One plant had over 15 potatoes on it – but only a few over 3 oz and most had 8 or more. If those had sized up to the typical 8oz+ …no I’m not gonna run that math, I’m getting faint from the possibilities! Sheet mulching an acre will take 400 yards of horse manure – this system isn’t for the faint of heart- but my “base” soil is deader than a doornail so a larger trial at the farm on rich soil will be on the docket for next year.
As others have found, and I have begun to suspect, there was no addition tuber set that I could attribute to the deep mulch – the spuds were located low on the vine as usual, but the soil was evenly moist and full of worms. Harvest was a breeze, though not as easy as the bucket method – just pull the straw back, ruffle the moist, rich soil with your fingers, and pluck our spud, after spud, after spud, after spud. ZERO lost spuds to pitchfork foibles to boot. As a strip crop between young swaled permaculture tree crops this could be a VERY productive system to pay the bills as the chestnut / orchard comes on line. Plus from my experience you get a significant net INCREASE in organic matter and it is very close to no till.
Can organic farming feed the world? Show me a conventional farmer hitting 18,000,000 calories per acre .
FU Monsanto. You’re Round Up Ready? Big deal… this system is Peak Oil Ready.
Be the Change!
-Rob
PS: Here is a detailed and technical study of straw mulch for potato growing in Germany. Graphs – oooo shiny!
Filed under: compost, Energy Descent, Harvest, Market Garden 2009, Sheet Mulch, Small Scale Agriculture, sustainable agriculture | Tagged: Potato Farming | 31 Comments »
One Straw: Be The Change 
