Hi Christo, You have a nice looking plant. I am not an expert on 'dragon fruit' plants. Maybe someone with more knowledge will come along.
I bought these 2 about 18 months ago on a whim. They were the same size as yours. I shouldn't have. This is not a good growing zone for them. They can't handle temps below 40 degrees and it gets too cold here. But I decided to keep them in large pots and bring them inside in the winter. Dumb idea because they want to grow to 8-20 feet tall!
Anyway, This website is where I got the best info about growing them.
https://www.planetnatural.com/...
I have included a couple of pictures of mine and this is what I have learned....
Most of the websites said to put them in full sun. When I first did that they looked like yours, very dry and pale green. Too much sun. Lots of stuff in my yard gets sun-scald from the screaming hot summers. So I placed them here on the south side of my house. They are under a small overhang so during the hottest 4 months of the summer they are in super bright light all day long but not direct sunlight. They liked that a lot and turned very dark green. Now, as the sun is going lower in the sky they are just starting to get some direct sunlight.
I put them in peat moss, perlite and sand with just a little good soil but the pots drained water too fast and they were shriveling up. So I added about 2 inches of good soil to the pot to retain more water. Now, at this size, I give them almost a gallon of water once every week or two. They like that too. I put a towel around the pots so the roots won't roast in the sun.
They want to climb up something. So I put large tree limbs in the pots. They send out roots and grab onto the wood. I do pour a small amount of water down the wood which helps the plants roots to stay soft and grab onto the branch. We have very low humidity here so molds are not a problem. Then I dump the rest of the water in the pots.
The websites all say to fertilize them regularly. I haven't given them any fertilizer at all because I don't want them to grow fast. I will have to move them through this door into the house this winter. What was I thinking!
And, last fall when I was moving them into the house a segment broke off one plant. So I just stuck it in a small pot and it rooted quickly. It's been living under a shady tree this summer. I put it in the picture too for you to see in the little pot. Because it has grown long it had flopped over and was laying in the dirt. It was trying to root there.
Now that I know they will grow and root happily horizontally I think I will try to move them to my greenhouse this winter and lay them out on a long table. Place some wood under them so they have something to root to. But the light isn't as bright in there so I might never get fruit. But I can always cut off some segments and root them again and try something else.
Happy gardening.
