Rehoboth Homestead

Here is what you see when you walk into our hoophouse in the winter.

The white stuff is a spun poly like interfacing used in sewing. It adds about 4° F protection when it gets cold but is well above freezing. Below freezing, the colder it gets the more protection it can afford. I have used this set up for several years, based on work at Michigan State which showed that moisture condenses and freezes to the row cover when the temperature gets below freezing, and in their work it stayed a minimum 17°F under the row cover even when below zero outside.

I didn’t get greens seeded in September, and finally dug some out of the field right before freeze up in late November (maybe it was December even).  The soil could be covered with many plants, but I just experimented with a few rows since I didn’t know how they would take such late transplanting. The results are that I don’t recommend it, but we are getting a few salads for our personal use and the chickens/ducks/geese are appreciating them. Here is what it looks like under the row cover:

I’ve been taking temperature readings and not finding that much protection. I only have two leads on the thermometer, one not under the row cover and one under the row cover, so don’t have temperatures outside the hoophouse. Here is a sample of what we’ve recorded:

in tunnel			under row cover
min	max		min	max
28.6	35.0		30.7	36.8
22.6	72.6		25.0	83.5
23.8	53.5		26.0	62.2
15.2	67.0		19.1	77.3
18.4	62.9		21.6	75.5
10.2	34.3		14.2	35.7
8.5	67.0		12.9	67.8
22.2	44.7		24.5	47.4
16.8	64.7		20.2	73.6
14.4	51.3		17.9	61.2
8.4	61.5		13.1	70.6
13.0	52.0		17.4	61.7
20.2	35.6		23.0	31.1
28.6	35.0		30.7	36.8
7.1	50.7		11.7	54.0
10.5	52.0		14.7	53.1
22.3	63.7		24.6	64.1
18.8	42.2		21.8	45.1
3.4	36.0		8.2	37.8
-2.6	52.5		3.0	56.4
47.3	44.4		49.3	53.8

On sunny days it is maybe 10 degrees warmer under the row cover. This speeds plant growth and also warms the soil so it stays a little warmer at night. As you can see, though, it has gotten below zero inside the hoophouse and close to zero under the row cover.

But many of the plants are surviving. Apparently protection from the chilling and drying wind allows some plants to survive under colder temperatures than they would without protection from the wind and ice. I even have rosemary plants out there and they seem to be doing well.

I changed the thermometer so I will be able to compare outside temps with inside the hoophouse temps.  Here are the first readings:

in tunnel			outside
min	max		min	max
10.2	75.3		-0.7	38.0
8.3	63.9		47	27.7
21	88.6		15.8	35.7
19.5	66.1		12	31.9
17.7	86.7		12.4	43.2
16.2	86.7		12.9	48.6
19.6	75.1		16.6	38.3
30.8	64		26.7	47.4

When we get some sunshine, the hoophouse really warms up nicely. It looks like the biggest benefit is from the two layers of hoophouse plastic on the hoophouse. A big question then becomes: which is more beneficial – a few degrees of protection from the row cover or more light without the row cover?