Tag Archives: Four-Season Harvest

Building a Cold Frame

16 Sep

I was driving around northern Michigan today and noticed some of the leaves starting to change color. Then I realized that with the first frost date rapidly approaching, it was time to think about protecting my garden. Plants such as basil and peppers won’t tolerate temperatures below 50 degrees Fahrenheit let alone a frost. I suddenly felt the urgent need to harvest everything before it was too late.

You can extend your growing season long into the fall, maybe into winter in a small unheated greenhouse or cold frame for some crops such as carrots, beets, spinach and arugula. Remember how early spring came? I got so tired of covering and uncovering plants. Hot, cold, hot cold. Well, nighttime temperatures are what you need to pay close attention to now, and the covering and uncovering is about to start again. If it is going to dip down below that magic 50 degrees, protect your warm season vegetables like tomatoes which can tolerate an occasional dip, but then you will start to notice how the fruits stop maturing and they aren’t turning red. Best to pick them and make some fried green tomatoes. If you want to seriously continue to garden and save what you can, you can build a simple cold frame. WARNING!!! You can now cook your cool season crops on a sunny day. So not only do you need to keep them warm at night, you need to keep them cool on a sunny day. For now, protect with newspaper or lightweight fabric such as a frost cloth which is available from Johnny’s Selected Seeds. Protect this way on these occasional frosty nights, and prepare for colder temperatures by building a simple cold frame like I did here.

I cut 1/2 inch PVC pipes 10 feet long. Since my beds are raised it was easy to push them into the ground on one side. The bed that I am working on is 4 feet by 8 feet. I have equally spaced 5 PVC pipes (you only see part of it here).

I bent the PVC around and pushed into the ground on the opposite side of the bed.

I secured the PVC to the inside of the raised bed using this galvanized piece.

Then I used zip ties to secure an 8 foot pipe to the top. I would recommend adding a screw to prevent it from sliding down the sides.

Cover with poly. Here I used a horticultural grade poly that I had left over from a greenhouse we built at our farm. You can buy this at greenhouse supply companies or catalogs like Farm-Tek. More light penetrates, which is important for plant growth and development.

Notice how transparent it is.

This was an inexpensive alternative using painters plastic from the hardware.

For finishing touches, you can use scrap pieces of wood screwed to the bed frame to secure the poly at the bottoms. I used pink foam insulation pieces for the ends to make it easier to remove on sunny days to prevent the temperatures from getting too high.

This was the simplest and most inexpensive way that I came up with to make a cold frame. There are many other options to explore whether you want to protect your crops, extend your season, or get a jump on next year. Click on the Grow Veg link to the right, or below on the links to go to Amazon for my favorite books to learn more. Or the last link to a Juwel Cold Frame like the one you see in the background of the above picture. This is one of my favorite cold frames. Just ignore the snow for now. We still have a lot of time before that gets here.

Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long

The Year-Round Vegetable Gardener: How to Grow Your Own Food 365 Days a Year, No Matter Where You Live

Juwel Cold Frame 1000

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Spinach

4 Mar

Spinach, Spinacia oleracea L., belongs to the Chenopodiacea family, a.k.a., Goosefoot family where it originated in Central and Southwest Asia. An annual in our garden where it prefers to grow during the cooler seasons of spring and fall. The leaf types of spinach are either “smooth” which is somewhat flat like in this picture, or “savoy” which is wrinkly looking. In the warmer months it will “bolt” which means it will quickly produce it’s flower to make seed, thus slowing down leaf production, which is the part of spinach we like to eat. If you choose to collect seed though, summer is the best time to do that. Whether prepared fresh (my preferred method) or cooked, Americans consumed about 1.8 pounds per person per year in 2004. As far as world production of spinach at that time, China grew the most, followed by the U.S. and then Japan. Spinach is made up of about 91% water, and nutritionally, per a 100 gram serving, spinach provides about 2.9 g of protein, 0.4g fat, 3.6 g carbs, 2.2 g fiber, 99 mg calcium, and 2.27 mg iron. Go Popeye! Long ago in England it was said that spinach was used as a dye for Easter Eggs.

 

spinach seed

You can plant spinach as soon as the soil is workable or right now if you have a cold frame or low tunnel. Seeds will germinate in 5-6 days with soil temperatures about 70 degrees, 12-23 days with soil temps at 40-50 degrees, and up to 63 days at 32-39 degrees. I like to start my spinach indoors to ensure quick germination and then transplant outside about 2-3 inches apart in rows 8-12 inches apart. When the soil temperature gets above 50, I’ll sow seeds directly in the soil. Lately it has been hovering around 40 degrees in my cold frame.

 

Spinach prefers full sun but will tolerate some shade. Maintain a soil pH of 6-6.8. Spinach prefers to grow with an air temperature ranging from 40 degrees Fahrenheit to a maximum of 75. It is not susceptible to chilling injury which makes it a good pick for a fall/winter/spring crop. When grown under ideal conditions, you will be able to harvest leaves when mature about 37-45 days. It is best to harvest in the morning, wash, and store what you don’t eat in the refrigerator. In Eliot Coleman’s book, Four-Season Harvest he recommends the varieties “Tyee” for spring, “Steadfast” for summer, “Space” for autumn, and “Space” or “Winter Bloomsday” for winter. I have grown “Space” and “Tyee” and have been very happy with them both.

Starting to plant my early spring crops means that the gardening season is beginning! Even though we are experiencing the coldest temperatures and the most snow we have had all winter, my head is busy in the garden. I wonder if this is a disorder of some type. My family would say so. If you haven’t already, make sure you check out the garden planning tools at GrowVeg.com

My Urban Farmscape Winter Garden

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