Steve Peek writes:

On Wednesday, June 24, 2015 at 12:39:49 AM UTC-4, Mike Spencer wrote:

Two years now, most broccoli plants have headed out very early, giving
2" to 4" heads. In the past, with same or similar soil and
manure, we've flourishing plants that yield 12" to 14" heads.

Any suggestions to remedy this? Identify the likely cause?

Perhaps your soil has gotten low on boron. Boron is a micronutrient
that is necessary for good cole crops. The addition of a little
laundry additive (Twenty Mule Team Borax) will solve the problem is
this is the cause.

It's possible. Trace elements are a problem in Nova Scotia due to
soils and heavy rainfall. We use seaweed for mulch which should help
with some trace elements but maybe not boron. I have borax on hand so
I can turn a little in around the replacement seedlings.

OTOH,the UMinn. Extension service [1] suggests that boron deficiency
leads to "hollow stems with internal discoloration" but blames small
heads on immature plants on "nitrogen deficiency, cold temperature
shock to young transplants, drought stress or other factors that
markedly restrict vegetative growth". The only one of these that's
very likely to have affected us is too much cold for the young plants.
We had a light frost or two after they were planted.

Thanks for the boron pointer. I knew about boron problems with
turnips but not cole plants.


- Mike

[1] http://www.extension.umn.edu/garden/...-in-minnesota/

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Mike Spencer Nova Scotia, Canada