Best option for water run

After three years of using a Flowerhouse pop up greenhouse to winter store our tropicals, we decided to keep it up this spring for veggies. This helps keep the squirrels out. This past winter I had 4 15 gallon water barrels stored in the greenhouse.

We plan to buy a Palram 6x8 greenhouse. I intend to add a solar powered solar water heating system to the green house. Dakota’s lithium has a simple diy kit.

The question is: do I pump the hot water during the day through the existing barrels of water or should I dig a pit and run the water though a gravel bed to warm the floor?

I have a plane for running it through the gravel, but I am not sure how to run one pump pull or push water through four barrels.

HEY NOW! We 'squirrels' need to eat too!

You can bleed off heat under the gravel if you do not insulate between the gravel and the earth.
Unless you have a pretty thick layer of gravel.

Heating gravel has many benefits.

Just like floor heating in your home, you will get more even heat and less drafts.

Wet gravel is more efficient except for the higher humidity.

Too bad you couldn't place a storage barrel in each corner and pipe the heated water from outside through the gravel first then into the barrels.

Even if those barrels were merely 5 gallon water jugs. Every bit helps.

Many plants benefit from warm soil.
This is why they sell heating pads for plants.

Insulating the greenhouse would be very beneficial.

But what about summertime? You can cook your plants if not careful.

There are ways to dissuade squirrels from your garden.
I read that they do not like the smell of coffee grounds. They also do not like cats.




Or, if legal where you live, you could live trap them and relocate them.

Flower bulbs: sprinkle talcum powder on the bulb after you toss it in the hole. Squirrels won't bother it then.


Edit: fix typo

first off, if i could get the squirrels drunk or install a flipper, i think the neighbors would call the po po

I was not sure how much heat would be transferred out of the water into the gravel before the water reaches the existing barrels if they were connected.

I thinking it will be best to have a valve to open or close the floor piping.

I was going to line the barrels up on the north side of the greenhouse, and connect them with a fill pipe that can push the water up from the bottom to the top of each barrel.  then have a gravity fed release from the bottom that can go back out to join up with the out from the floor and cycle back through the system.

I'm just not sure if the gravity flow will be enough to run without a pump.
Attached is a the complete as of now.