Technical Protocol 3.0
Greenhouse Planting of Tissue Culture Transplants
Well-rooted plantlets in plastic boxes with air vents can be transplanted with high success rates following this protocol.
The primary sign of an effective transition process is greenhouse
acclimated plantets within 7 days. To accomplish this it is very
important to make sure that the plantlets never ever wilt, not even a
single leaf should wilt. At the same time, plants need to adjust to
greenhouse conditions, so minimum extra misting or fogging should be
used. We have formulated this protocol based on our own experiences and
those of our customers, to be inexpensive, versatile and highly
successful. We have even been able to transition plants to open field
conditions, using this type of approach.
Shipping is stressful
We do not recommend transplanting to soil immediately upon receipt of plantlets.
Upon receipt, each plantlet box is opened, plantlets are sprayed with a mild antitranspirant, the entire shipment is covered with seedling cloth and misted lightly with water. Over the following 2 days plantlets are misted lightly as needed while they recover from shipping.
Transplant to soil gently
After 2-3 days, plantlets are removed from the agar and planted into soil. Weaker plantlets, such as Million Bells, may need a full dip in antitranspirant, other plantlets need just another light spray. Plantlets are watered in thoroughly, set on benches and covered with the seedling cloth. Hand misting is all they need. Heavy mist is not recommended.
Transition should take a week
After 2 days the seedling cover cloth can usually be removed. Check the plantlets 2-3 times for the first few days and mist by hand lightly as needed. If plantlets show any sign of wilting, replace the seedling cover cloth and hand mist. Drench the trays daily as you would for seedlings.
If you prefer to use mechanically misted benches, please use the finest droplet size you can and set the mist for infrequent short bursts. Waster sitting on the leaf surface delays the cuticle development and the plantlets will take longer to get adjusted to open bench conditions.
We recommend Cloudcover (Easy Gardener, Waco, TX) as a suitable, light antitranspirant. We use the recommended rate: 10% of the concentrate in a water spray. We will include a bottle of Cloudcover with large shipments.
The purpose of the transplanting protocol is to push the plantlets into independence as quickly as possible, while not allowing them to wilt, EVER. If the weather is hot, or very dry, time the planting in the greenhouse for the early evening or late afternoon hours, to minimize the first day shock. After 3-5 days, check a few of the plantlets for signs of new leaves and root tips. As soon as there are new white root tips it is time to remove the black shadecloth. As soon as there are new leaves it is time to remove the white seedling cloth. Generally, remove the coverings at night, even the first day, to keep the air fresh and reduce disease. Never use automatic mist at night, it encourages disease, slows growth and creates leaves with no effective cuticle.
This method was used in California in August to field plant 1/2 acre of watermelon plantlets with 17 days between the laboratory and the field and losses of less than 5% in the greenhouse and less than 1% in the field. It was 108F when we planted the greenhouse and it was 105F when we field planted, so this method can work very well.
This method was used for potatoes in Chile with very good results, even after the plantlets had been in dark shipping conditions for over 1 week.
For less extreme climates we recommend removing the black shadecloth as early as possible.
Daily Recommended Schedule
(Suggest you print for reference)