Technical Protocol 5.0

Field Planting Of Tissue Culture Transplants

Older well-rooted plantlets in plastic boxes with air vents can be adapted for direct-to-soil transplanting into trays for field planting in less than 3 weeks from laboratory to open field.

Summer Protocol

General Guidelines

The purpose of the following protocol is to push the plantlets into independence as quickly as possible, while not allowing them to wilt, EVER. If the weather is hot, time the planting in the greenhouse or field 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, it encourages disease, slows growth and creates leaves with no effective cuticle.

This method was used in Woodland in August to field plant 1/2 acre of watermelon plantlets with 17 days between the laboratory and the field and loses of less than 5% in the greenhouse and less than 1% in the field. It was 108 F when we planted the greenhouse and it was 105 F 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
Day    Time    Day     Notes
-24 PMMonday Take plantlet boxes to greenhouse, remove lids, spray the plantlets with 10% Cloudcover, lightly place lids on top of the boxes for the night, cover with Seedling Cover Cloth (white 30%), left open at the ends to let some air through.
-17 AMTuesday Remove box lids entirely, loosely cover the boxes with seedling cloth.

NOTE: if conditions are dry, may need about 2T water in each box, otherwise dries out a little too quickly and agar may get too hard to remove easily.
07 AMWednesday Soil Mix:
  • 8 pt. Supersoil (fert. booster included)
  • 4 pt. perlite
  • 1 pt. vermiculite (#2 grade)
Remove plantlets from the plastic boxes, wash agar off, trim roots to about 1 inch.

Dip shoots in 10% Cloudcover solution to cover upper and lower leaf surfaces.

Plant so that about 1/4 inch of stem is beneath the soil surface and all roots are submerged. (Note: Never leave the newly planted trays in the sun or without drenching with water when going on breaks or lunch).

When a tray of plantlets is full, apply a thin layer of Vermiculite to soil surface and drench the soil to make a good root-to-soil contact throughout the plug.

Cover transplants with Seedling cloth (white 30%) and mist the cloth so it is lying directly on the upper leaves of the plantlets.

Cover entire plantlet plug tray area with 30% black shadecloth suspended or supported 1-4 inches above the seedling cloth and again mist from above to wet.
 1 PM  manual misting
 5 PM  final spray for the day with fine water mist
110 AMThursday manual misting
 3 PM  manual misting
 6 PM  remove shade and seedling cloth covers for the night
211 AMFriday replace shade and seedling cloth covers for the day

should be able to see small 1/8 inch white root tips apparent on few plantlets lifted up out of the soil.
 4 PM  Remove shadecloth and seedling cover for night.
310 AMSaturday water in plantlets and replace seedling cover for the day
 6 PM  Remove shadecloth and seedling cover for night.
411 AMSunday water in plantlets and replace seedling cover for the day
 6 PM  Remove shadecloth and seedling cover for night.
510 AMMonday Should be able to see some newly expanded leaves. Water in plantlets and replace seedling cover for the day.
 6 PM  Remove shadecloth and seedling cover for night.
610 AMTuesday Replace the seedling cloth only, should not need any more shadecloth.

water in plantlets and replace seedling cover for the day
 6 PM  Remove seedling cover for night.
710 AMWednesday Roots should be coming out bottom of Jiffy pots, new leaves expanding rapidly.
810 AMThursday Fertilize with general mix (15-15-15 Peters) (plantlets should now be field plantable under cups w/ manual watering)
98 AMFriday Do not need any cloth covers anymore
Water in mornings as needed
Keep in full sun on top of bench.
108 AMSaturday Keep in full sun on top of bench.
116 PMSunday Move trays with well-rooted plants outside onto a cool or grassy area, open sun.
12 Monday Outside plants should not wilt, but growth will slow down.
13,14,15 Tuesday
 Little new growth of leaves, should be hardening up for field planting.
Field Planting
1610 AMFriday Should be able to plant in open field. Plant in late afternoon or early evening - not in mornings or during heat of day. Do not plant on a windy day.

Make sure the field is watered well before planting starts.

Plant so that the plantlets are buried partially. Only about 4-6 leaves should be left out in the open air. Water in very well.

If field conditions are unusually hot or windy, place a clear plastic cup over each plantlet and push a little dirt up around it for 2 days. Punch a nail through the top of the cup to let in some air.