Starting a coldframe

[Paradox]

After the debacle with a few of my trees freezing and getting dehydrated in the garage last year, I decided to build a cold frame for my most hardy trees. I am building the walls out of cement block against the north side of the house. It will be 3 blocks high (roughly 22.5 inches tall) and giving me almost about 3.5 x 7.5 feet of space to put trees in. I will have a heavy duty 1/4 inch screened top over the top of it to keep the vermin (VMC) out with the option of putting a 4x8 sheet of plywood if necessary. As designed it should provide a nice wind proof area for the trees.

My questions are: Should I dig down below grade to put the trees in the hole and cover with mulch or can I just put them on the ground as is and cover with mulch? I am concerned that if I do dig a hole, it will become a puddle with the copious amounts of rain we can get around here in the fall and spring. I could dig a hole and fill it with gravel up to grade to provide drainage.

I havent used this method to winter trees yet so I would greatly appreciate any suggestions people might have.
Here is a picture of the first layer of block roughed out on the ground.

Thanks

 

[Dav4]

I think you will be fine leaving it at ground level. The cement block wall will provide a solid wind break and being close to the foundation will provide some ambient heat to the cold frame. If that area doesn't drain well in winter, you may want to raise the pots off the ground with bricks or something similar before covering them in mulch. Having a solid hardware cloth screen on top is a good idea, but I would still assume some critters could squeeze their way in. Moth balls in cheese cloth bags might help vs baited spring loaded traps. Hopefully, you'll have better off this winter.

 

[Paradox]

The moth balls is a great idea that I didnt think of. I have a bunch of polyester filter bags I can fill with moth balls and spread them around the cold frame.
Ill put those on the list of things to get.
Thanks

 

[JudyB]

I dug below soil level, then fill the excavation part way up with gravel. Then it can drain, and you still get below soil level. The most recent ones I've used a plastic dura bench top instead of gravel, same idea, but the bench is easier as it's level. They are an open grid bench if you're not familiar with them. Concrete block is a good retainer of heat, one of the best substances for that.

 

[Paradox]

I dug below soil level, then fill the excavation part way up with gravel. Then it can drain, and you still get below soil level. The most recent ones I've used a plastic dura bench top instead of gravel, same idea, but the bench is easier as it's level. They are an open grid bench if you're not familiar with them. Concrete block is a good retainer of heat, one of the best substances for that.

How far did you dig down?

 

[fourteener]

I'm with Judy. My first cold frame had no drainage and the first year I opened it to see that my trees were sitting in standing water. I would say six inches of gravel is adequate, but I would also include an escape route of gravel on your lowest corner. Dig out a trench underneath those blocks you have in place on the lowest corner, fill it with gravel too. Like an easy french drain without the pipe. Water will escape the easiest, lowest way.

 

[GrimLore]

How far did you dig down?

I have a method that will save you a lot of headaches. In my avatar that gravel area is 57 feet long and I figured out a way to drain it forever... I then had the 5 1/2 ton of crushed stone delivered and put it down - never once had a drainage problem. PM me for my phone number as explaining it will probably take 5 minutes and typing it would take forever

Grimmy

 

[JudyB]

How far did you dig down?

Around a foot. Just enough to set the durabench in, pot on top, then mulch over the pot to soil level.

Sorry I didn't see your question until now...

 

[Paradox]

I have a method that will save you a lot of headaches. In my avatar that gravel area is 57 feet long and I figured out a way to drain it forever... I then had the 5 1/2 ton of crushed stone delivered and put it down - never once had a drainage problem. PM me for my phone number as explaining it will probably take 5 minutes and typing it would take forever

Grimmy

I can PM you if you want and arrange a time to talk with you. I am going to be away part of this weekend.
I know you said typing would take a long time......but I am sure others would like to know this info as well.....

Right now I scraped the area with a shovel so its all level. I dont think the area has a problem draining but I am going to put the trees on benchtops that I will lay on the ground as a precaution.
If it works and I think I need to excavate and fill with gravel I can do that next year when I have more time.

 

[GrimLore]

Right now I scraped the area with a shovel so its all level.

I will try to explain in steps and then outline why in a summary -

1)Mark the parameter for reference and remove the blocks.
2)It does not have to be an extreme grade but the surface should be on an angle so it drains toward a lowest point just beyond where the blocks lay.
3)Damp it down to compress it a bit and let it dry.
4)Cut, as someone mentioned channels often called French Gutters from the highest to the lowest points - 4 inches wide, 3 inches deep.
5)Cover the soil with 8 mil plastic vapor barrier and leave it about 10 - 12 inches extended beyond where the blocks will be. Trim after reinstall with a razor later.
6)Fill the gutters only with any type of course stone, gravel, pebble, etc...
7)Run the hose over it and note it drains quite well. At this point put the blocks back in place. The gutter exits should be under the blocks but still allow flow under.
8)Now you can safely use it or dress the plastic(makes no difference)
9)If you do I highly recommend using something that does not rot(no natural mulch or wood) Use rubber mulch, gravel, pea stone or similar.

Done in that fashion you will eliminate a lot of "possible" problems. Anything in there allowed to rot regardless of drainage will often result in fungal problems and could result in bacterial problems as I had at this property(not where I used to live). Standing water invites insects, algae, and unpleasant odors. Being on the North side the sun will not be helping you much drying it out so I would strongly advise taking the extra time down the road to reconstruct for those reasons. On another subject Moth Balls - do not let them come in contact with the soil or surface in any way if they are allowed to get wet and dissolve they do severe damage to the soil. A jar on its side containing them with air holes in the upper portion of the lid keeps them in check.

It sounds complicated but I assure all of you it is important and really not difficult or expensive...

Grimmy

 

[Paradox]

Stupid question:

How far out from the block wall on the low end should the gutters extend?

And you mean use rubber mulch or gravel to "mulch" the trees in instead of pine bark mulch or similar? Or you mean just to put over the plastic and under the trees?

 

[Cadillactaste]

Sandy...I'm excited for you! Winter protection offers a huge relief when things get nasty for us northerners. I can't wait to hear of your success come spring from your project.

 

[GrimLore]

How far out from the block wall on the low end should the gutters extend?

In my avatar the gravel/rock filled gutters extend 3-4 inches under the fence. I used larger 3 inch or so rock around the ends to discourage critters.

And you mean use rubber mulch or gravel to "mulch" the trees in instead of pine bark mulch or similar?

I was referring to a thin top dressing over the plastic which is really not needed(just for looks really). If you are additionally mulching in the pots you won't see the plastic anyways. Myself for mulch or insulation I would not use organic products(they rot). My favorite is Pine Horse bedding. It is processed pine chips that do not rot and are very inexpensive. Any farm/tractor supply should have a bag of it for 5USD or less. It is quite compressed in the bag and I "think" in your case that one bag would be sufficient.

Stupid question:

No question is stupid and I expected my description would need further detail

Grimmy

 

[Paradox]

Thanks Grimmy, much appreciated

Sandy...I'm excited for you! Winter protection offers a huge relief when things get nasty for us northerners. I can't wait to hear of your success come spring from your project.

I have wintered trees the last 3 years in my unheated, attached garage. I didnt have any troubles until last winter when the trees nearest the door froze solid for 3 weeks and the air was very dry. I dont know if this will solve that problem, but I plan on putting my more hardy trees in this structure and mulching them in. If it snows, I plan on letting the snow bury them further. We will see how it works.

 

[Cadillactaste]

Thanks Grimmy, much appreciated





I have wintered trees the last 3 years in my unheated, attached garage. I didnt have any troubles until last winter when the trees nearest the door froze solid for 3 weeks and the air was very dry. I dont know if this will solve that problem, but I plan on putting my more hardy trees in this structure and mulching them in. If it snows, I plan on letting the snow bury them further. We will see how it works.

What a booger that it worked for such a time then failed...fingers crossed we hear positive spring awakening from you!

 

[GrimLore]

We will see how it works.

I am certain you will be pleased. When I had plants I found Wintering them outside in proper conditions was always best and also the least work.

Grimmy

 

[Paradox]

I put the trees in the cold frame 2 days ago. I put a remote temperature sensor in there. This morning it was 15 degrees outside and 31 in the coldframe. Very pleased so far.

 

[whfarro]

Glad to hear things are working out.
What temp sensor are you using? I have been looking for one for my garage.

 

[JudyB]

I put the trees in the cold frame 2 days ago. I put a remote temperature sensor in there. This morning it was 15 degrees outside and 31 in the coldframe. Very pleased so far.

That's great!
Do you have any auto venting to open it if it gets too warm in there?

 

[Cadillactaste]

That's great!
Do you have any auto venting to open it if it gets too warm in there?

Something I want to look at whenever we get done with my husband's man cave/garage,workshop area...because that means shakes on the building is used as a greenhouse.