Crop rotation

In Mort Bay Community Garden we grow a wide variety of crops, which all need a plant-specific set of nutrients and are challenged by different pests.

Growing a sequence of different types of crops in any one bed over subsequent seasons is called crop rotation, a strategy already practised by Middle Eastern farmers 8000 years ago, to maintain a productive and healthy soil.

Growing the same type of plant repeatedly in one spot

  • depletes the soil of the nutrients that this specific plant needs and will finally lead to an imbalance in the soil
  • will lead to a build-up of soil-borne pathogens and pests that are associated with that particular crop

We classify or crops by plant family and growing properties into the following groups. We aim for a planting sequence where plants out of any one group are only planted every fourth season in the same spot.

  • gourds or cucurbits
  • nightshades or solanums
  • legumes
  • cabbages or brassicas
  • onions or alliums
  • leafy greens
  • root vegetables

There are several factors, that we consider when we plan the crop rotation:

  • crops from the gourd and the nightshade family only thrive in the warm months of the year and need long days with lots of sun
  • leafy greens, like lettuces will bolt very quickly in hot summer conditions, they thrive best in Spring and Autumn
  • root vegetables and alliums work very well together, they prefer a cooler season, but picking the right cultivar makes them thrive in Summer as well
  • root vegetables like a nutrient poor soil, they shouldn’t be planted after legumes, they work very well after cabbages
  • most brassicas thrive best in cooler seasons
  • cabbages, gourds and nightshades are heavy feeders
  • legumes add nitrogen back to the soil, if the roots are left to rot in the bed after harvest

The diagram shows an example of a crop rotation plan that takes all these considerations into account.