Summer heat and Andean crops

This was a pretty normal year on the coast of Washington.  We had a cool winter, a cool spring, a cool summer, and so far, we’re having a cool fall.  We’re close enough to the ocean that the temperature of the Pacific just off shore is a much better predictor of our temperatures than anything else.  Our range is about +/- 15 degrees F versus the average water temperature that ranges from about 55 degrees F in summer to 50 degrees in winter.

Here is the temperature graph for the hottest three months of the year, taken right here in the garden:

Washington coast – daily temperature range

The high temperature for the year was 74 degrees and that day was the only day that the temperature exceeded 70 degrees.  We stay in a very comfortable range all summer, with most of the day falling between 50 and 60 degrees.

Here is a chart for the equivalent growing season in Cajamarca, Peru, a city around which many of the traditional Andean tuber crops are grown:

Cajamarca Peru – average temperature

These graphs show different things – one is showing the daily range, while the other is showing the average temperature, but you can see that the Cajamarca temperatures would slot in pretty nicely between the high and low lines for our local temperatures.

Cajamarca is at an elevation of 9000 feet in the tropics, while we are at sea level in the temperate zone, but our temperatures are very similar.  Both climates are similarly humid at the equivalent times of year. The only major differences are (1) that the Andes gets very intense sunlight as a consequence of elevation, while we have a foggy lowland climate and (2) that the Andes are much drier in the winter, so that frosts are less damaging to crops than they are here.  And, of course, day length is different, which presents some challenges for crops that are dependent on that.

The similarities are what drew me to the Andean crops.  We fail to grow things here that people can grow pretty easily even five miles inland, like corn, tomatoes, peppers, cucumbers, and squash.  Melons, okra, or sweet potatoes?  Forget it.  It can even be tough to get a decent crop of beans.  This is not a common problem in most of North America, where growers can usually count on summer heat, even if the season is short.  We could have three months of morning fog with clear skies the rest of the day and still never develop the heat units necessary to mature corn.

On the other hand, potatoes, oca, ulluco, achocha, mashua, and yacon all grow very nicely here.  And we have some other Andean crops under evaluation that also look promising.  So, rather than try to fight the climate, we’ve transplanted a little bit of Andean agriculture to the Washington coast and it is working out very nicely.

Now the real trick will be to find ways to make improvements in these crops so that they can be enjoyed in a wider range of temperate climates.

Most of the Andean crops mentioned in this post are available in our seed shop.

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