Kai Gardens Trial

Does planting cabbage over winter shorten the time to harvest?

Experiment:

  • Research has shown that most plants stop active growth when day length is below 10 hours. In Auckland, this occurs from end of May to the end of July.
  • Even though temperatures on Waiheke are mild in winter, plant growth is also affected by day length - this experiment will check whether planting in winter speeds up the harvest time.

Materials and Methods:

  • Vegetable - Cabbage Globe
  • Soil - Sheet layering compost with various organic materials
  • Blood and bone fertiliser

Plantings

  1. End of May (10 hrs light)
  2. End of June (9.5 hrs light)
  3. End of July (10 hrs light)

Parameters to measure:

  • Observe visual growth by counting leaves and measuring diameter
    • This was interrupted by COVID-19
  • Observe growth and judge when the cabbage is ready to harvest using cabbage head firmness and size.

 

Results

  • End of May planting: harvested after 12 weeks (mid-August)
  • End of June planting: harvested after 16 weeks (early Oct)
  • End of July planting: harvested after 14 weeks (early Oct)

Trial Conclusion

  1. Planting the cabbages over winter did not shorten the time till harvest.
  2. It is better to plant cabbages either before the end of May, or after the end July, when there are over 10 daylight hours per day.
  3. From this experiment, we can tentatively conclude that the results would be the same for other crops planted over the winter period.

First planting

Photos taken 17th June

First Planting Measurements

Visual observations (7 weeks after planting)

Plant 1: Plant 4:
Diameter - 39cm

Leaf count - 14

Diameter - 49cm

Leaf count - 12

Plant 2: Plant 5:
Diameter - 42cm

Leaf count - 14

Diameter - 42cm

Leaf count - 12

Plant 3: Plant 6:
Diameter - 46cm

Leaf count - 14

Diameter - 42cm

Leaf count - 12

 

 

 

 

 

 

 

Second Planting

Photos taken 25 June

Second Planting Measurements

Visual observations (2 weeks after planting)

Plant 1: Plant 4:
Diameter - 17cm

Leaf count - 5

Diameter - 15cm

Leaf count - 6

Plant 2: Plant 5:
Diameter - 16cm

Leaf count - 6

Diameter - 12cm

Leaf count - 4

Plant 3: Plant 6:
Diameter - 17cm

Leaf count - 5

Diameter - 11cm

Leaf count - 4