California is a region of microclimates. Travel a short distance, be it in elevation change, proximity to the coast, north to south, east to west or simply in distance measured in miles, and you are likely to experience significant changes in temperature, precipitation patterns, exposure to and duration of fog. Driving from Santa Cruz to San Francisco, one typically goes from cool, foggy conditions to warm and dry, to hot, sweltering, back to cool, even cold, foggy, grey skies.

Here in Santa Cruz, these microclimatic differences are most evident in annual rainfall totals and the duration/intensity of fog-specific locations experience during the fog season, i.e. June through August. In Santa Cruz proper, situated on the edge of the Pacific Ocean, annual precipitation averages 30″ per year. Boulder Creek, only 10 miles away in the Santa Cruz Mountains, averages 49″ per year. San Jose, only twenty miles from Santa Cruz, but sitting in the rain shadow of the coastal mountains, receives only 15″ of rainfall per year. Differences in the frequency and duration of fog cover are similarly pronounced.

In Santa Cruz the fog typically rolls in off of the coast by 6 p.m. and does not burn off until noon the following day. Upwards of three weeks a year, the fog does not retreat at all and entire days will be cool, overcast and unfavorable to the entire range of warm-season crops. In Boulder Creek the fog normally does not appear until well after sunset and burns off by 10 a.m. Rarely does the fog linger long enough to reduce the intensity or growing potential of the sun.  Over the hill, San Jose is almost never affected by fog and, buffered by the Santa Cruz Mountains, will usually be 10-20 degrees warmer, a giant difference for heat-loving, sun-dependent, warm-season crops.

At this point you might be asking ‘How is all of this relevant to flower growers?’. The “summer” of 2011 has been a particularly challenging one for coastal growers hoping to produce warm-season crops. Vegetable growers in particular have suffered from the “June gloom” through “Fogust” weather. Crops like gomphrena, celosia and pumpkin on a stick, which in warm years do reasonably well on the coast, have all been a disaster this year. Similarly, canopy diseases like rust, mildews and blight have all been thriving in our cool, damp conditions. As a result of microclimate differences, these challenges have barely cropped up for inland growers.

What can this teach us about our flower programs? Focus your crop planning and production around what produces best for you with the least amount of inputs and extra effort. Of course, these need to be crops with a strong market demand and that are profitable to produce, but if they are well suited to your environment, they will likely be less expensive to produce, both in terms of inputs, energy costs and labor from seed to harvest. A core principle of agroecology is to design agricultural systems that are based on your local and regional ecology, thus mimicking nature rather than struggling against that which we have little ability to control. This should be obvious, but often we strive to produce exactly what the market “expects” rather than what your climate genuinely supports. 

Of course, greenhouse, hoophouse and low tunnel production are an entirely different matter. Here, through the wonders of season extension, season enhancement and climate modification, we are readily able to produce that which might not easily grow outside. Here on the damp, cool coast, inside the dry warmth of the hoophouse, I have tomatoes thriving when all of our outside plantings have been overrun with late blight, and  were disced into the ground weeks ago. Other growers in our area are having similar successes with warm-season flowers under the cover of plastic. While I am not a big advocate of the supplemental heating and lighting, apologies to everyone who does benefit from these inputs, it is truly amazing what is possible, virtually year round and virtually in every growing region, with the addition of hoop houses in your growing regimen.

Christof Bernau

UCSC Center for Agroecology

Christof Bernau UCSC Center for Agroecology Contact at [email protected]