Renae Writes: High Tunnel Tomatoes

With the fall equinox approaching the cool nights are a threat.  Well maybe I am a little premature on the thought, but we did go ahead and put the plastic endwalls back up on the high tunnel.  The high tunnel is where we planted the first of the tomatoes back at the beginning of April and yes you are still enjoying those tomatoes!  After a little adjustment with the soil and figuring out how to moderate the temperatures in the heat of the summer we had a successful year with the tomatoes.  We had tomatoes in the high tunnel at least 3 weeks before our outside tomoatoes started to turn, and now hopefully we can prolong the tomato season with the endwalls up. 

The high tunnel is a 90’ by 30’ unheated structure that’s temperature is controlled by venting (i.e. wind blowing through the tunnel) and a misting system.  It is completely enclosed in the shoulder seasons during the winter, and during the nights in the shoulder seasons.   The two long sides have vented walls that roll up and down during the day.  And in the summer the endwalls are completely removed and the sidewalls rolled all the way down to allow for maximum ventilation.

Last year was our first year growing in the high tunnel, and the summer’s heat proved to be too hot for the tomatoes, reaching into the low 100s by 10:30am.  This year, we isntalled a mister system that extends from the rafters and would be on constantly from 11:00 am to 5:00 pm throughout most of July and part of August.  The mister system kept the temperature just where we wanted it--in the low 80s, even when it was in the high 90s outside.  We worried that the added moisture might lead to fungal disease, but we never saw anything, thank goodness.  We always made sure we turned off the mister with enough time for the tomato foliage to dry before nightfall.

Even with these cool evening temperatures, the high tunnel will hopefully continue to ripen tomatoes for another month or more.  The only conflict is that we'd like to get in there to plant our winter greens!  I guess we may just have to think about putting up another high tunnel...