In mid-February, we planted the greens that we expected to transfer to our greenhouse in a few weeks when the cold temperatures subsided, and the weather became a little more mild.  (See my post Planting into the Polar Vortex)

Any signs of spring around here in March?  Nope!

Any signs of spring around here in mid-March? Nope!

As we all now know, warm weather was still many, many weeks away.  We had a couple of salads from the thinnings of our seedlings, and moved them throughout the day to get them the maximum sunshine as they grew with gusto in front of our dining room windows.IMG_3734IMG_3735Meanwhile in our unheated greenhouse built against the south side of our barn, we prepped the growing boxes and deployed max/min thermometers.   In past years it has been warm enough to transplant into the greenhouse by early March.

The soil temperature began to break the 40 degree mark, but the air was still dropping well below freezing at night.

We read about deep winter greenhouses in Minnesota.

That’s when we got the idea to create a greenhouse within the greenhouse.  Many outdoor gardeners make use of row covers.  We brought the concept inside, and hoped the sun’s warmth building daily in the soil of the growing boxes could keep plants out of the killer-frost range — so we fashioned a framework and covered the beds with plastic sheeting.

IMG_3719We plan to put grommets in the plastic and hang it from dowels, so we can put it on and take if off easily.  We expect it will also be of great use extending the season in the fall.

IMG_3742The seedlings were really ready to stretch their toes.

IMG_3744We have lettuce in the foreground, spinach and kale in the background, and plan to fill the foreground open area with herbs soon.

Popeye never had it so good.

Popeye never had it so good.

The little darlings have been out in the greenhouse for four days now, and they are thriving.  We no longer need the plastic interior cover.

Salad days are just around the corner.


How are your early starts coming?


4 replies

  1. You have our normal winter weather and I suspect we may have yours and so I’m not very organised. I have planted some seeds in the greenhouse though and used fleece or row covers over the top for the still below freezing nights. Have you read the book “Four Season Harvest” by Eliot Coleman? It is a great book, not for just explaining how to extend the season, but also for noting what he tried and didn’t work – I think this aspect is really useful, because as he says, somethings might work elsewhere for others.

  2. We live in zone 4a and own a 26′ x 40′ greenhouse which is totally unusable in the winter months. I was looking for some ideas on how to utilize the space as a greenhouse within a greenhouse. I have 200′ of roofing cable which I could use as a heat source for the bottom and then build a frame work to attach vapor barrier to enclose an area half the size of the greenhouse. My plan was to force my mandevilles, dahlias and canna lilies to an early start. Anybody have any opinions, ideas etc. on this? All is gratefully appreciated! Thank you

    • Hi Andrea, that sounds like a good idea to me. We have used the greenhouse within greenhouse idea by draping plastic sheeting over the planter boxes in our greenhouse to extend the season on occasion, and have had success.

  3. I think the plastic draping is good, still need a steady heat source, not sure the heating cable is the best way to go. Apparently, they can’t be left on for long periods of time. I may have to take over hubbies workshop!

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