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Tuesday, April 15, 2014

Grafting Tomatoes

I'd been hesitating about trying this grafting of heirloom tomato tops onto hybrid roots.  The benefits seem genuine (vigorous and disease-resistant roots growing complexly-flavorful heirloom tomatoes).  But it seemed complicated.  Growing rootstock and heirloom tomatoes so the stem sizes matched, cutting both the stems so that the cuts matched, fastening a small soft silicon clip to hold the pieces together, creating an enclosed humidified recovery, etc.

I knew I wanted to try it, but I don't have "soft steady hands" and some of the humidifying arrangements I saw on the internet seemed elaborate, but I thought about it all for a while.

Well, it was certainly easy enough to plant enough hybrid and heirloom tomatoes for both grafting AND backups in case all the grafts failed.  I found the silicon clips at several sites and ordered some a month ago. I had stumbled across a 4-shelf plant stand with a zippered plastic enclosure for keeping plants warm outside and I realized that it was a fine humidifier device if I filled the lower 3 shelves with pans of water (later).
I had a razor Exacto knife) for cutting the stems.  I even had a 4" piece of wood cut at a 45 degree angle left over from the trailer work!  My goodness, I had everything I needed!

So with the trailer work complete and it being a rainy day, I collected everything on the basement workbench (and after some thought through the procedures, brought a few things upstairs to a table with good light).

It seemed to me the pattern was to transplant the hybrid rootstocks from little 6-packs to individual 3" pots to allow root growth, bring them all upstairs with the silicon clips and razor blade, fill the lower plant stand shelves with pans of water, and then make sure I had enough labels for all the new grafted heirloom tops.

That's when I realized I had made a serious mistake.  I hadn't examined the silicon clips carefully when the y arrived.  They are an "8" shape, but with one"o" larger than the other (like a snowman bottom and a snowman head).  I had assumed the larger "o" was for the tomato stems.  NOPE!  The clipping part was the small "o", and about as thin as pencil lead.  I should have done the grafting when the tomato seedlings were about 3" high, not 9"!

So I tried something creative and resourceful.  I used the larger "O" part!  I eyeballed the spot on the rootstocks where the stem size matched the "O" and cut a 45 degree angle above that.

Then fit the silicon clip ofer the cut stem and slid it down to where it was snug.  Made a new cut just above that.  Then I eyeballed the heirloom tops ("scions") and cut below that to be careful.

Testing the fit, I cut the scion stem narrower until it "just" fit into the "O" and matched the angles snugly.
I hope that all makes sense.  I used the silicon clips to measure the matching stem diameter and set them together at the matching angled cuts.

To make sure I didn't confuse the heirloom tops, I only brought one variety upstairs at a time , and made sure I had enough (and only enough) variety labels for each.  Because when you cut off the tops of the rootstock tomatoes and the tops of the heirloom tomatoes, they sure look a lot the same!

The other surprise was how FAST the grafted heirloom tops just wilted!
I did not realize how FAST plants transpire.  In just 15 minutes, the first grafted tops had wilted right over like cooked lettuce!  The enclosed humidity and darkness of the recovery chamber is supposed to help with that.  I I think I will also spray the tops several times per day.  The tomato grafting sites say the grafts need about a week of darkness along with the humidity, so after I zippered the plastic cover, I tossed a sheet over the whole stand.

Wish me luck!

And the first concern is resolved.  The enclosed stand with the pans of water on the other shelves caused the plastic cover to fog up within just 2 hours.  So the humidity is high.  And below the stand is a thick towel on a sheet of plastic so the drip won't damage the wood floor.  I may not think of everything in a new project, but I sure try!

I'll have some idea about the success in a few days.  If the grafted tops  are more erect in a few days, it means they are receiving moisture from the roots and the graft is healing.  If I recall enough from high school botany, the zylem and floem (one sends nutrients up and the other down) will be working and the connection between rootstock and scion top will be solid.

And if they fail?  Well, I have enough heirloom seedling and 2 Big Beef hybrids for the standard plantings of past years.  I'm no worse off.

But my big surprise is that it seems a lot easier that I feared.   It just took trying it to do it.


Megan said...

Very interesting Mark. As I suggested before, I think you should seriously consider writing this experiment up for publication in a gardening magazine.

Like many projects, there's some time and thought involved in getting everything set up, but once you've done that preparation the actual 'doing' is straightforward and doesn't take very long.

I'll be very interested to see how things progress.

Sydney, Australia

Andrea and the Celestial Kitties said...

I can't wait to see how they come out! Is shelf in the house then? Because I bet some kitty might try to get in there for a nap at some point, lol. You know how it is, all new things must be inspected!