GardenFork – Eclectic DIY

Tag: season extender

The Mini Greenhouse Repair Fail

You’ve probably seen one or three of my mini greenhouse plans videos. The most recent one talks about the complete fail of the plastic cover in the middle of winter. Here are the photos that show my attempt at repair before the complete breakdown of the covering.

My big mistake 4 months prior to the fail was to put screws through the top of the PVC pipes, and then lay plastic sheeting over the screw heads. Who knew that the metal screw head would eventually puncture through the plastic, starting as all holes do, small.

Prior to the small hole caused by the screw, all was good in the mini greenhouse. These rosemary plants had over-wintered well. Not so well after the plastic ripped though.

My attempt at repair was to use packing tape over the screw head and the splitting plastic. I knew it was not a 100% guaranteed repair, as it was cold out when I applied the tape. I don’t think other tape would have worked either. The glue on tape is not cold friendly.

That small hole grew through the winter, with the weight of heavy wet snow, and lots of wind. Then we had even more wind and that caused the complete tearing of the mini greenhouse cover. Darn. It sat for a while before I was ready to walk over and deal with it. Besides, there was still 18″ of snow on the ground. I knew all the plants inside the hoop house were toast.

Going forward I will use UV rated greenhouse plastic, I’ve seen some that is reinforced with netting in the plastic. AND I will screw the screws into the PVC starting underneath it, through the wood crossbeam, then into the pipe. If you have some old storm windows on hand, you can make a neat cold frame with them.

In the meantime, check the video where we walk through the fail:

May 3, 2017
Hoop House Cold Frame #2 – DIY GF Video

This is the second DIY Hoop House Cold Frame we have built in our video series. Easy to build, this mini greenhouse allows you to grow plants in winter. Watch the video here, plans and photos are below as well as links to our other DIY Hoop House Cold Frame Videos.

This cold frame uses a wire mesh that’s usually used for concrete, but it works really well as a cold frame form to hold the plastic up. I like how it works
You can buy this concrete reinforcing wire at a local lumber supply yard. It comes in two thicknesses, you want the thinner gauge wire, the thick wire is too much, I think. This wire also comes in rolls, but the it is a pain to work with. The mesh I bought was 10’ x 5’.

To cut the wire mesh we use a right angle grinder with a metal cutting disc. Be sure to wear ear and eye protection and wear gloves while you’re handling this material, it can cut your skin.

Be sure the cut end of the wire mesh faces the plywood end, else the plastic can get sliced by the sharp ends of the wire. You can put pieces of old garden hose along the end of the wire mesh where the plastic bends over to form the end wall, as well as on the plywood end to protect the plastic from the hard edges of the wire and wood.

But you can build this! It’s not hard and I really like it. Another great version of the hoop house cold frames that we’ve built, we have a whole series of them – link here – and every time we make one we get better and better. The super cool part is that you can extend your growing season in the fall and you can use one of these cold frames to warm up the soil in your vegetable beds in late winter and plant seeds even earlier than you could normally. Cold frame hoop houses are especially good for salad greens, radishes, sugar snap peas – plants that are cold tolerant.

You can use scrap wood to tie the corners together, or use brackets.

The automatic vent that we use is kind of a specialty item but that they’re not that expensive. Here is the link to buy it.

You could put one vent in or you could put in two vents. With two vents you would put plywood at both ends of this cold frame. Having a vent on both sides allows more warm air to exit. Cold frames can get quite hot, you don’t realize how much solar energy the sun has even in the winter. You will need to vent the hoop house, you can go out on sunny days and manually vent it if you want by lifting up the cold frames, but I’m not there all the time. So I like the automatic vents.
Have you made a cold frame? Do you have anymore questions? Pease leave them in the comments below.

My cold frame experiences have been greatly influenced by these books by Eliot Coleman and Niki Jabbour.

Four-Season Farm Year Round Vegetable Gardener (affiliate links)

Watch more of our hoop house cold frame plans videos here.

PVC Cold Frame Hoop House #3 – DIY GF Video

February 7, 2015
Seed Starting in a Hoop House Cold Frame : DIY Video

Starting seeds in a hoop house cold frame is like putting a greenhouse on your vegetable bed. The hoop house warms the soil and then you drop seeds right into the soil. No transplanting or grow lights, no transplant shock. This is our cheap PVC hoop house that can be made with salvaged or recycled materials, and then you can grow vegetables in the hoop house. What I love is how the cold frame warms the soil to 15F above the ambient soil temperature.

Plants that do well for seed starting in a hoop house are those that are cold tolerant. What the cold frame offers is a warmer soil and air temperature, which aids in germination. Yes, peas can be planted in snow, but they germinate much better in slightly warmer soil, same for lettuces and cabbages like kale, just a bit warmer and they sprout better. For this video I put sugar snap pea seeds in and radish seeds. Radishes are one of those seeds that are kinda fail-safe, so you feel ok even if some of the other plants didn’t take as well.

We have several videos on how to build a hoop house cold frame and how to use a plastic greenhouse like this, here is the video of us building our first cheap hoop house. I think its key to have the thermally controlled vent, if it gets too hot, you might consider putting a vent on each end of the hoop house. The PVC we use in this cold frame could be salvaged or recycled from another project or job site. The plastic we use is 3 mil plastic from the hardware store. With care this plastic will last several years. In the middle of summer, I hang my hoop house on the back side of the woodshed, and the plastic stays in good shape for a few years.

Salad Greens Grow Really Well In A Hoop House

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April 9, 2013
Hotbeds

A couple of weeks ago Eric and I were talking on Gardenfork Radio about his new DIY Cold Frames video, and I mentioned winter gardening in hotbeds. I’d seen some hotbeds in the garden in Colonial Williamsburg, where they still garden the way colonial people did.

3 feet deep and lined with bricks to hold and distribute the heat.

Hotbed are like Eric’s cold frames with glass on top and all, but deeper. Last weekend we went up to the Williamsburg Farmers Market for their big pre-Thanksgiving holiday market and I took some pictures of their hotbeds to show Gardenfork readers.

What makes hotbeds particularly attractive to the DIY organic gardener is that you get a twofer. First, you use the otherwise wasted heat of composting to get an early start on Spring. Second, you have fresh, finished compost to spread on your garden.

A hotbed needs to have a mass of at least 1 cubic yard to be effective. That’s because what you’re building is a compost pile and compost needs mass to really cook. So these beds are deep:

— It helps to line a deep hotbed with plastic sheeting or weed block fabric to aid in cleaning it out in the Spring.
— Layer in browns (cabon): dry leaves, leaf mold, spoiled hay and bedding from a stall.
— Layer in greens (nitrogen): kitchen waste, fresh manure.

Hotbeds are an excellent use for chicken manure as well as horse manure, which can be “seedy” in the compost otherwise. Cattle manure is good too.

If done right, enough heat will be generated to kill all seeds, worm eggs, and pathogens. In fact, hotbeds have been known to combust and smolder if too big. Obviously, you don’t put compost worms into a hotbed to help with the composting unless you want them to cook.

add 12 inches of rich growing soil onto the top of the fresh manure.

— Add about 12 inches of good soil for growing.

— Carefully manage your glass frames so that your plants don’t overheat.

Hotbeds are an ancient method of sprouting seeds and growing plants during the winter, Aristotle mentions the Egyptians using compost piles to sprout seedlings. Europeans imported hotbeds from Arab countries after the Crusades.

In fact, the colder and more sunless your winters, the more hotbeds will help you get an early start on the spring garden and bridge what was called in early colonial America the Starving Time, January to March, after harvest stores from the previous fall had run out but before plants would grow in the frozen fields.

Hotbeds don’t have to be buried, either. The Romans had hotbeds on carts so that they could be moved under cover when it rained. In medieval Europe, hotbeds were frequently just dung heaps that people planted vegetables into over the winter.

Manage your hotbeds like a coldframe. Overheating is as dangerous to your plants as freezing.

But regardless of how you build your hotbed, proper timing is important. Few plants or seeds can tolerate the intense heat of an early hotbed. So start your hotbed a month or two before you plant. So plan to plant or seed on the backside of this period, when the hotbed is warm but not hot.

And remember, you have to manage the moisture content of your hotbed, just like a compost pile; neither too wet nor too dry.

And when you hear on the news that a place is a “hotbed of political activity” you’ll know what they’re full of. ;->

November 21, 2011
Video: Cold Frame Plans from Brooklyn Botanic Garden

Last week we visited with Patty Hulse at the Brooklyn Botanic Garden, who showed us the cold frames they built and use throughout the winter. Very nice. Thanks to my friend Tony, ( the man who knits ) for helping with the camera. An episode on knitting is in the works.

Greens growing in a cold frame at the Brooklyn Botanic Garden

December 15, 2006