Tomatoes: Grafting Guide

Tomatoes: Grafting Guide

If you want to up your tomato game, here is a way that you can explore nature's talents. Our 'Fortamino' Rootstock Tomato has been specially selected for its impressive disease and stress resistance, vigorous root growth, and increased flowering and fruit size. 'Fortamino' is a hybrid tomato variety that is intended to be used as the rootstock (the root portion) of a grafted tomato plant. Grafting is joining two separate plants so they may function as one. The grafting method is used to create a robust plant that has the impressive qualities of two plants. This labor-intensive practice requires patience and precision but will undoubtedly pay off in the long run! Below are some tips, tricks, and information that will help you graft your way to success.


  • A razor blade or graft cutting tool
  • Grafting clips, optional small stakes or wood skewers that fit the clip for seedling stability
  • Sanitizer for sanitizing cutting tools and clips as you work
  • Labels
  • Scion and rootstock plants with similar sized stems.

We recommend building a healing chamber in sanitized, humid, dark conditions and out of direct light. This can be as simple as a sanitized tote container or using black plastic to cover the healing seedlings.

Step 1: Sow the tomatoes that you would like to graft together (e.g. 'Fortmino' Rootstock and Pineapple Pole Tomato). You will want to sow more than you need and sow every day for a few days in a row to try and attain similar stem sizes for the graft(s).

The diameter of the rootstock and scion stems need to be the same size for cambium to develop and successfully grow.

You should start grafting when seedlings are 2 to 3 weeks old, about 6 inches tall, and fit your grafting clips.

Step 2: Select your Grafting Cut (Cleft or Splice)

 cleft demo

Cleft—made at a 90-degree angle to the rootstock stem, below the cotyledons; then make a vertical cut about 1/2'' deep right down the middle of the rootstock. Secure the grafting clip below your cuts. Slice both sides of the scion stem to create a tapered wedge, similar to a flat-head screwdriver, which will fit in the cleft of the rootstock. Gently push the scion into the rootstock cleft and secure the clip around the union. The clip may be secured to a stake for added stability.

splice demo

Splice—made about 1/2" long and at about 60-70 degrees to the stem of the rootstock plant below the cotyledon. Attach the grafting clip to the cut rootstock to create a tube for the scion to be inserted into. The scion cut is made below the leaves in an area of the stem that matches the diameter, angle, and size of the cut on the rootstock. Slide the scion into the clip, so both open cuts face one another and create a union. Clip together. The clip may be secured to a stake for added stability.

Step 3: Post-Graft Care

Place grafted plants in the sanitized healing chamber with 90% humidity, temperatures between 72°-85° F, and low light. Misting freshly grafted plants helps prevent wilting and raises humidity.

Day 3—Slowly introduce light to the plants in the enclosed area, increasing exposure every subsequent day.

Day 5—Begin reducing humidity with the goal of achieving conditions close to those they will be in after healing.

Day 7—Remove grafting clips and gently bend stems to ensure grafts have healed and don't separate. If they separate, replace the clip and check again in a day or two.

Our plants are living organisms that are constantly working to survive, grow, and reproduce! It can be fun to explore different growing techniques to achieve maximum crop yield and expand upon our botanical knowledge and experiences, even if it's a humbling journey. We hope you try grafting with our 'Fortamino' Rootstock Tomato! It provides you with incredible disease resistance to Fusarium crown and root rot, Fusarium wilt, leaf mold, tomato mosaic virus, verticillium wilt, root-knot nematodes, and tomato spotted wilt virus. And not to mention, it increases flowers per truss and fruit weight. Yes, please!

Tomato and grafting anatomy
Terms to know

Written by Madeleine Pesso

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