[Market-farming] edge of bed grows better

waldenfarm waldenfarm at bellsouth.net
Tue Mar 8 08:04:00 EST 2011


I saw the same thing early on in my farming career, except with carrots. Carrots on the edge of the bed were full size, ones in the middle were small but uniform in size. I asked my mentor, Steve Rioch, about this and he answered in his usual way by asking ME a question. That is, he made me figure it out based on what he had taught me about soil management.

What he taught me was that we can only manage 4 things in the soil:
    -soil air through tillage, or no tillage
    -soil water through irrigation, or drain tiles
    -soil organic matter by adding compost &/or green manure crops, or reduced tillage
    -soil minerals

So which of these is restricting plant growth? I had done even tillage (double digging) on the beds, I was careful to water evenly and the compost and minerals added had been spread evenly. So it wasn't soil air or nutrients. The plants on the edge couldn't have more room for root growth into the paths because root growth & nutrient uptake are both oxygen demanding processes- the plant has to have oxygen present at the root to grow & have the energy to extract nutrients from the soil.

I was stumped until I remembered an illustration on drip irrigation in different soil types to determine how far apart to run drip lines. In sandy soils the water drained almost straight down and did very little wicking (capillary action) to the sides. The more clay in the soil, the wider the water moved sideways. My soil is fine sand & silt with no clay. That was the "aha" moment. I also remembered that carrots, like most root crops, require more water than others. 

I also noticed the compacted soil in the paths looked moist. I figured water was wicking from these "moisture reservoirs" into the edges of the bed. Next carrot bed I concentrated water in the center and irrigated longer & more often. Result- large, uniform size carrots.

Are you using the "sandy loam" as a sandy loam that is fertile or as a soil texture term? I would guess that your "sandy loam" has a low clay content and you're not getting sideways movement of moisture. That's one of the main challenges with a sandy soil with little or no clay- The soil mineral particles hold very little water and water drains pretty much straight down.

The old outdoor thermometer is telling me it's warm enough to go out & put in the strawberry plants, so I'll check back after dark.

(And thanks to all those who gave me recommendations on plant sources.)

Alex McGregor
Walden Farm

  ----- Original Message ----- 
  From: Avalon Farms 
  To: 'Market Farming' 
  Sent: Monday, March 07, 2011 8:55 PM
  Subject: [Market-farming] edge of bed grows better

  Does anyone know why the mesclun on the edge of the beds grows 10 times faster/better than the rest? They are 3 ft wide beds in a hoop house. Fairly even moisture and fertilizer. But the plants on the outside of the beds always grow better. The only thing I can think of is that the edges naturally get compressed a bit more and the centers stay fluffier. This soil is sandy clay/loam.


  Thanks in advance,


  Avalon Farms
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