One of our most frequently asked questions is “When is the best time to plant?”. Traditionally our two planting seasons in Central Otago are spring and autumn. Both have their advantages, but spring gives you the most growing time possible before winter, while autumn gives plants the best chance to get roots established while the soil moisture levels are high, minimising drought stress. If planting in summer, irrigation is recommended.

The answer to the question could be different for every person, plant and project, but generally we prefer autumn for planting. This is because where we are, summer drought is both the main limiting factor for growth and the biggest risk for plant survival. By planting in autumn, plants are given as many good growing days as possible before summer comes back around. The hope is that by that time roots will have grown deeper into the ground where the water will remain in summer. We tend to plant from April after a few good downpours as the ground is moist enough for planting, while still holding enough warmth for roots to grow. Warm autumn soils will facilitate good root growth, more than in early spring. Plants generally need temperatures of 10 C or above to grow roots and shoots.

With that said winter and spring are viable times to plant, despite less time for root growth before summer. Due to the cold temperatures of winter and early spring plants planted in these seasons will be dormant but the plants will be in place for when the temperatures rise and growth begins. There are times when spring planting is preferred over autumn planting, for example, when planting species where frost tolerance is a concern. Many plants bought from nurseries and garden centres are young - young plants tend to be less frost tolerant than after they are established. Thus, if the plant species is on the margin of being able to tolerate frost in the planting site it may be a good idea to plant in spring so it has the longest time possible to get established by the following winter. Furthermore, plants from garden centres are often shipped from areas with different climates and need weeks or months to acclimatise to a cooler climate.

Without this time to develop hardiness, the risk of succumbing to frost is higher. The risk is reduced if these plants are planted in spring after the hard frosts have passed (generally October - November). If plants are grown locally in the same climate as the planting site then this is not a problem. Spring plantings may need more irrigation than autumn plantings to grow over the dry season, but irrigation requirements depend on the site, plant choices and planting treatment.