Compost Windrow as Greenhouse Heat Source
Note to readers, attached is the complete annual report for FNE09-675.
We continue to research other compost heating projects and potential improvements/innovations. Since the concrete pad is very permanent, we are seeking ideal construction and trying to avoid the need for potential changes or updates to the system. Once we were comfortable to being construction late last fall/winter, we learned from our concrete supplier that we really should let the concrete "cure" for at least 30 days prior to use. Otherwise, the new concrete would likely develop significant cracks from the rapid, extreme temperature changes that moving a pile of warm compose on and off the pad would create. Since the pad would have embedded liquid-filled tubing, there would be a risk of damaging the tubing and/or developing leaks in the tubing.
We are not comfortable with our design and plan to begin construction in August such that we will have plenty of time to cure the pad prior to heating season. Also, we will have something to show and discuss with International Plant Propagator's (IPPS) conference tour participants on October 1st. For more information on the conference, see http://www.ipps.org/EasternNA/meeting.htm and see Tour B at http://www.ipps.org/EasternNA/tours/conference_tours.html
We may adjust need to the footprint/size of the concrete pad to account for changes in material costs since the original grant budget was created. We will make a final determination on this when we verify prices with concrete and tubing vendors this July/August.