We sow our first hoophouse spinach in the ground around September 7. Because it’s too hot in the hoophouse at this time for spinach seed to germinate, we pre-sprout the seed for a week in the fridge before sowing. This is very easy, much easier than growing beansprouts!
We measure out the amount of seed we’ll need and soak it overnight in a jar of water. We use 1oz (28 g) of seed per 90ft (27.4 m) row. We use a cup measure or a tablespoon that we keep in the spinach seed bucket. 7T = ½ cup. 1T=15 ml. It’s very roughly ½ cup per row. We use Mason jars and replace the flat metal lid with a piece of screen of some kind, metal or plastic, with holes smaller than spinach seeds. The Mason jar lid band holds this in place.
In the morning we drain off the excess water, and set the jar in the fridge on its side. Once a day we rotate the jar to even out the moisture and therefore hopefully the rate of growth of the shoots. After about a week the seeds have grown a short white root 1/8” (3 mm) long and are ready to sow.
When there is extra moisture with the seeds they can tend to clump together. One solution to this problem is to mix in a dry inert material like corn grits, as in the first photo, to make the seeds easier to sow individually. This year I tried a different approach. I spread out a scrap of rowcover on the ground and spread the seeds out on that to dry the surfaces. This made the seeds easy to sow, but I noticed that several white rootlets were left behind on the rowcover. I don’t know if the rowcover Velcro effect caused this or if it was a higher rate of damage than the grits treatment. It wasn’t a significant amount.
Replacing bubble foil
We have a 3 ft (1 m) length of a foil and bubble-plastic roll material along the base of the north wall in our hoophouse. The north side is the coldest, and not a lot of direct light comes in there, that low down, so we decided to insulate from radiation losses and also get some light reflection back there. I think it works well, although I have not measured anything to see if my impressions are backed up by reality! We put the hoophouse up in 2003 and we have replaced this “bubble foil” once since. Definitely we left it too long since we last changed it. As well as big rips, we had micro-crumbs of plastic flaking off. Not what we want in our food!!
I pulled off the old stuff, using an office staple remover to extract the old staples. I reused the scrap driptape we had been using as batten tape (still years of life left for it in that role!) My approach to agricultural plastics is to buy the most durable and treat them gently to make them last as long as possible. We had two partial rolls of the bubble foil material in the shed, so I used those, but found myself 14 ft (4 m) short, so we had to buy some more. I don’t know about durability, but the Reflectix product was the sturdiest at the start. How long would this stuff normally last? Two changes in 2003-2019 = 16 years. 8 years is too long! 6 or 7 seems like it might be OK. Ask me in 2025!
Removing the shadecloth
In the summer we cover our hoophouse with a large sheet of shadecloth. We pack it away in the second week of September. (It helps if the first bed of winter crops (planted September 6-7) has had a chance to germinate before we make it hotter in there by pulling off the shadecloth.) Our shadecloth is 50% knitted polyethylene. I think 45% would be better than 50%, next time we buy. And I think buying 100 ft (30 m) would be better than just the 96 ft (29 m) length of the hoophouse. See the way the shadecloth pulls away from the ends in the photo.
We are still using the shadecloth we bought in 2004, 15 years later. It has a few mouse holes that happened in storage, and the fabric is starting to lose its strength and rip. We used to fix snap-on grommets to the center-line of the shadecloth at the ends and tie with ropes onto the end wall structure. But nowadays the shadecloth is too weak to withstand the firm pull we need to give to get those ends in place. So we get a hot spot at each end of the hoophouse. We’ll need to buy new shadecloth in the next couple of years. Probably we can cut the old piece up into 7 ft (2 m) strips to use over beds of lettuce outdoors. It won’t need much tensile strength for that task.