I am not having any luck grafting my citrus. It is a Meyers lemon and I am trying to graft onto it:
Grapefruit
Tangerine/Mandarin
Orange (navel)
Using the cleft method. Have also tried bud. NO LUCK with about 15 20 grafts so far.

On the other hand I did about 15 grafts on pear and they all took and about 49 onto appricot with various scions (plum, peach, appricot, nectarine) and about 43 took. Even one that I did on the main trunk and slipped/nailed a foot long scion took.

I AM NOT SURE WHY NONE OF THE CITRUS TAKE.. HELP. MAYBE JOE HAS SOME IDEAS...

We normally graft late October through February. This is when the trees are growing at there slowest rate.

On cleft graft you needto make sure that the scion and the trees cambium align very good atleast on one side. For t bud make sure the bark is slipping( when you can easily peel the cambium from the bark). If temps are up to 94 degrees keep it shaded above that use foil to cover the graft.

T-budding works best when daily high temps are in the 70s and 80s. I have had better luck with bark grafts than cleft grafts on citrus. Are you wrapping the scion with parafilm to the top? Are you sterilizing your tools and the stock and budwood with lysol spray?

Also, with T-budding especially, bud exposure time should be kept to a minimum. I even use the top of a bic ink pen to hold the corners of the T open so that I can insert the bud just seconds after it is cut.

If you haven't tried bark grafts, you should--look a Joe's tutorial and be sure to make those tiny cuts on the side of the scion. I like to do bark grafts on pencil size stock with toothpick size scions. Choose a fast growing limb for stock--I have a Ponkan bark graft that I did and posted a picture of several yrs ago--I think it was fall of 2007. That toothpick size graft is now over 7 ft and full of fruit.

have you ever tried chip budding?
It nearly always take with small root stock and scion.

For bigger root stock and scion cleft graft is better.