Archive for May, 2009

Broccoli is Hard to Grow

May 9, 2009

At least for me, onthe roof. 

The Problem with brocolli, is that it is a cool season crop, but it takes a fairly long time to mature.   Last year I put my transplants into their raised beds in early to mid April.   The seemed to grow fast, big, and hardy.  But by late June or early July when they began to develop their heads, the temperature of the soil was often above 80 degrees.  I tried to cool things down with shade-cloth, but the ambient temperature of the roof (it was a hot June, too) overwhelmed any coolness the soil might have retained.  On the roof, the soil will be the same temperature as the air, or warmer, as the roof  surface can go well into the 100’s–hot enough to burn skin.

I am devoted to brocolli.  When my wife and I used to get our veggies primarily from the grocery store, we ate brocolli almost every night.  One way or another, I determined, I would grow good roof-top brocolli.   So I started my seeds inside in mid-January, and planted good sized seedlings in the middle of February.  This brocolli would not suffer from over-heating. 

About two weeks ago the first  tight heads began to form and grew steadily larger and fuller.  But about a week ago something else happened.  Instead of growing large and tight, the earliest ones began to open and spread.  They was about to flower, even though the soil temperature dips into the 50s at night, rising to the 70’s, only, during the day.  Perfect brocolli growing temperatures.  What happened?

Apparently prolonged exposure to cold weather can cause brocolli to flower prematurely, to create “buttons.”  While still tasty, unlike the heat-caused bolting, these were paltry looking little sprouts–the brassilica version of Charlie Brown’s Christmast  tree.  I included them in the CSA boxes this week.  I hope my subscribers  remember the experimental nature of my project as they nibble on these gangly little guys.

The good news is there is another round of brocolli, about 2 or 3 weeks behind this one, just starting to form its heads.  They look tight.  They didn’t suffer the cold nights of February.  Perhaps they will grow large and tight.


Early Season Lessons

May 6, 2009

We’re now entering the 5th week of our CSA season.  This is very early for Wisconsin, as the terrestrial farmers are still as much as 4 weeks away from their first installment.  Despite what is in many ways a successful attempt to extend the season, I am concerned about the lack of variety.


My subscribers have enjoyed a decent quantity of lettuce (5 types), arugula, spinach, endive and escarole, Swiss chard, and kale (sweet, wonderful, kale).   They have also received approximately 2 radishes each.  If our own salads are any measure, the quality has been good.  Greens grown in this time are sweet and tender.  We are a month or more away from the first danger of a hint of bitterness.  Heat may be a greater challenge on the roof than cold. 


But I need to find a way to increase the variety and that is what I’ve been noodling on the last few days.  Certainly I can do better with overwintering some carrots and green onions, but what else?  I planted a lot of radishes, but the ones first seeded did not develop bulbs, even though they were a winter variety.   How early can peas be started, even in a greenhouse type setting?  They tolerate the cold, but the germination and early growth is so slow that the later ones soon catch up.  My attempt to start beans early was a bust, with very low germination rates.  Some of the ones started later and in the greenhouse-free area seem to be ahead.  Broccoli doesn’t like the heat, for sure.  But it also doesn’t seem to like the cold (more about that in future entries).  The cabbage is plodding along, but without any sense of urgency.  What about beats?  What am I forgetting?  Green is the color of our movement, but give me more of the spectrum!


Eliot Coleman’s techniques (see The Four Season Harvest and TheWinter Harvest Handbook—which I have not yet read) are promising, but did not work on the roof as well as I had hoped.  Where I had expected to find some carrots this spring, I instead found rotting carrot mush.  I can do better next year simply by planting a few winter crops earlier in the fall (the basic notion is that they are established enough by the time deep cold and low light sets in that, despite their relative dormancy, they can still be harvested) and by putting some carrots inside the greenhouse area.  I need some asparagus, but the urgent constantly overrides the important and I have trouble finding the time or space for something whose first harvest is 3 years off.


Perhaps I need something more radical.  Geothermal heat in the boxes? Better heat retention strategies? Solar reflectors? Time, money, and roof-load limits all interfere.  For now.  What hard-won wisdom has my generation lost?  What new techniques are we going to discover?