We are going to start our 2021 diary with a little experimentation. We haven’t grown watermelon for a number of years and have decided that we would like to try a couple of plants this year. After doing some research online we have decided we would like to learn to graft watermelon. Some of the benefits of watermelon grafting would be disease resistance and plant vigor. This will be totally new for us and we do not really know how it will turn out. We may have to grow traditionally if we can’t master the grafting process. Apparently, one of the most important things to have after grafting is to have some sort of healing chamber for the newly grafted plants to go into. This healing chamber needs to be kept at and a very high relative humidity at first and then slowly reduced over the course of a week. The grafts need to be in the dark for the first two days and then slowly introduced to light a little longer each day.
The picture below shows our newly built healing chamber (24” X 28” inside dimensions) with the control box on the right.
The control box contains a SHT2000 temperature and humidity controller. It is wired in such a way so that one half of the outlet supplies power to the humidifier and the other half delivers power to the heater. It is very easy to make changes to the settings to either raise or lower the heat/ humidity inside the box. The red display is the temperature and the blue is the humidity.
We started some seeds January 15 just for practice. We decide to use bushel gourd as the rootstock mainly because it was available to us. Unfortunately, we had very poor germination of the bushel gourds and we were only able to get 3 seedlings started from that batch. Today, we decided to try the first practice grafts. There are a number of different grafting techniques, but we decided for this first try to go with the one cotyledon graft.
This is one of the bushel gourd seedlings. They were not the healthiest looking plants but it’s all we had.
Here is the same plant after the true leaves as well as one of the cotyledons were cut off on an angle down the stem.
Next, is the watermelon scion that was cut on the same angle to hopefully match the cut on the bushel gourd.
Next a grafting clip was put on the stem
The seedlings were put inside the healing chamber and covered to keep light out. The humidifier is just a small bottle cap humidifier that fits inside a water bottle. The heater is a germination mat under the wire rack. The black probe on the top right is connected to the SHT 2000 controller. It measures both the temperature and the humidity.