Cold Frame questions...

Ok, so silly thing...

Over the fall I planted some cabbage and kale and stuff, they actually did very well - only in that they didn't actually die in my little covered creations until the second batch of below 0 temps. Which was kinda funny, because the Brussel Sprout plant lasted the longest, and I still don't know why the kale died first.

BUT I am putting out real cold frames (my last invention was plastic bottles and plastic wrapped cages I use to keep the ground hogs out - the snow eventually knocked the plastic in - I didn't think it through).

So, since the last batch was actually just a "yeah, that could have gone better"... I don't want to make the mistake of cooking my vegetables in the cold frame.

Based on all my research, the cold frame should have some neat little two liter bottles of water, and maybe I should put the plants in the plastic bottles like I did in the fall. BUT they are cold happy veggies, Kale, broccoli, cabbage, etc.

If I check on them every day, do you think they will survive temps as low as the low teens but be ok during the day when it gets to like 50? Or should I plan on opening them every morning?

I would love to hear what everyone here thinks.

This is my fourth year gardening... but the first two years the groundhogs ate everything I planted no matter how I did the fencing, and the third year I planted everything too close together (I got happy with the seeds), and last year they were a little too close and all my tomatoes got blight, though I did get a lot of tomatoes, but lost the garlic, cucumbers, and some of the corn and squash. Each year gets better... but I would love to have a longer season using stuff like cold frames.

Did you try posting in the vegetable forum? Might get more answers there.

Are your cold frames where they will get direct sun? and what material are they made of? Give us some specifics.
Gardening is a learning process for EVERYONE. I think no matter how long you have been at it, you learn new things every season or every time you experiment with a new plant or seed. That is one of the great things about gardening

Thank you, Jnette. I will if I decide I want to do a paid subscription. I have not decided yet, I would like more time with the site before I make that decision.

Nanny 23, I used 2 x 6 x 8s deck boards, but it is only the 6 at the top. I am using heavy duty plastic (I forget what the label said on it) and metal fencing to keep out any early rabbits and groundhogs.

They get sun at least 5 or 6 hours a day (even now). I am very lucky on the sun side of things. My backyard is wide open for the sun.

They are 2 x 8 raised beds (approximately, my woodworking is a process too). They will actually be pulled up and replaced with metal fencing around them as well (but not until the nights stay over 30).

Unfortunately, I am using a peat moss/vermiculate/potting soil mix..... next time I will use that other thing instead of peat moss, I watch all of Ray's Youtube videos so I am going to use his soil mix instructions next time.

I do not have a thermometer atm to test the temps, but I read in some of the university sites that the cold vegetables I picked should do good (except germination) as low as the teens, but would do better if the temps stayed above 30 and under 70. Germination won't occur in most below 40 though. But I already grew them in the house a bit, just they need to get out there this next week or I will start losing them.

>> They get sun at least 5 or 6 hours a day

If the cold frame is "tight" with no vents, I would have expected that to cook seedlings or plants!

I guess if the air is below zero, even direct sun MIGHT not heat it up to damaging levels, but I would really worry about heat with 5 hours of direct sun on a clear day.

>> If I check on them every day, do you think they will survive temps as low as the low teens but be ok during the day when it gets to like 50?

If the days go up to 50, and you get full direct sun for 5 hours, my thinking is "you should wait until AFTER harvest to steam your greens". But I guess it depends on how clear the plastic is and whether you have any air leaks.

Can you vent it some around 9-10 in the morning, and/or vent all the way when the day gets warmer than (say) 40, or the sun hits it fully?

Maybe mostly close it when the temperature drops in the evening.

And close it an hour before full shade reaches the frame?

I would stick my hand inside and feel the soil, as well as watching the plants for wilting during the day or frost damage in the morning.

And maybe throw an old sheet, blanket or tarp over the top after the sun goes down, if the night is expected to be extra-cold? Plastic is not a very good insulator. Mainly it keeps warm air from escaping and warm soil from re-radiating its heat instantly during the day.

I understand wanting to build up some heat in the soil and wood and water reservoirs, to "get them through the night".

However, maybe if they have tropical warmth during the day, you will get "soft" growth that can't take a chill at night.

But if you keep them "cool" during the day, they might stay more "hardened off" and better able to take 30 or 25 degrees at night.

But listen closer to people experienced with cold frames than to me!

When I use clear plastic over my vegies I make sure it will not overheat like this:
If the day is supposed to be just a bit too warm, and only mid day, I will open one end or one side, but mostly leave it closed. Opening one side or end means there is not a lot of air flow, so they do not get cold wind.
I might open both ends but leave the main cover over. This will allow more air flow, but still keep them warmer when the temperatures are marginal.
If the day is supposed to be too warm pretty much all day, even if it is a bit too cool in the morning before I go to work I will open it more fully, knowing that the cold is temporary, and it is not really all that much too cold. I would pretty much remove the whole cover, leave it lying in the path to be put back on in the evening.

I use tunnels, not individual covers.

You might do this:
Find several thermometers and place them in several of your containers.
Write down how hot it gets inside each container, and what the air temperature outside the containers is, and what the weather report predicted.
Do slightly different things to the containers.
Leave some closed.
Prop some barely open with a stick lying down.
Prop some further open with a larger stick, or a couple of sticks.
When you have a pretty good idea of how hot it might get under the containers based on what the weather prediction is, then you will know how much to open them or not.

On another website, we can leave "thumbs-up" or acorns on posts that we think are very valuable and deserve applause.

This one deserves five acorns!

Thank you everyone! I am sorry I am late getting back...

I actually did not finish my cold frames yet :( but my porch is staying above freezing so I think that with the suggestions here I can keep it safe.

Sadly, the bunnies are out and if my puppy's endless fascination with the groundhog hole is any indication, the groundhogs are awake too... which means pups will be wandering too. I have to redo the idea for the cold frames because they won't hold up to digging and attention of those animals. :(

I have tried most all the non-fence methods of keeping them out and nothing has ever worked, though I just added tons of mint to my garden this past year (growing rather just oil).

Also... I agree with you RickCorey - we should be able to thumbs up.... changes to forums are a pain though (from a programming side - or moving from a non-programming side). Most changes mean everything from the previous style has to be manually moved or lost.

There is a LOT of good information in here even if they design is a little outdated. :)

There are heat sensitive openers on the market that will help regulate the air flow and temperature automatically. These are affordable and are sized to lift a certain wt.

I always say err on the side of coolness. A plant can stand a little bit of cool but not a lot of to hot. That's my story and I am sticking to it.