How to plant in season with climate change

May 14, 2013 - PRLog -- Food plants will always grow better in the right climate and if planted at the optimum time of the year. Unfortunately for most food gardeners, this logic is often very easily blurred by the commercial interests of plant and seed sellers and by planting recommendations which are too general or have not adjusted to climate change.

Plants are their most sensitive to temperatures when they are young. As they gain their strength, the range of temperatures they can withstand expands. For annual plants such vegetables, herbs and grains, the planting and growing temperature ranges are fundamental to their vitality. For perennial plants such as fruit trees, the time of year for planting, although important, is normally not as sensitive as it is for vegetables, but cooling or chill requirements during the year have a significant impact on the success of a large number of fruit trees.

Other perennials such as Australian native plants are very robust in Australia's climate, but they are still subject to climate ranges and will grow very well in the right climate, but will struggle with a temperature range which is not ideal for their climate profile.

When you go to your local nursery or monstrous hardware store that sells plant seedlings, they are likely to have a wonderful and enticing range. If you ask them if it is the right time to plant, they are very likely to say yes. What else would you expect since they are for sale?  A large proportion of those seedlings may have been grown in temperature controlled environments which are very different to your local climate when you buy them.

When you take those fragile seedlings home and put them in your garden, they may die if you do not care for them properly, but they will definitely perish or be stunted if the temperatures outside are not appropriate for the plant. As a gardener, you could easily become discouraged at this point and you may give up or go back to the nursery and they may suggest you buy some “organic” fertiliser, because, perhaps your soil is not right, which may be quite true. And so it goes with spending money on food gardening, just look at the shelves of stuff in any nursery.

You may be a keener gardener and want to grow from seed. Seed packets normally describe the times of the year to plant a seed and have different ways of describing this. Some use numbered zones, others use zone descriptions such a cool temperate and temperate, sub tropical and tropical. While others use more traditional seasonal descriptions such as, spring autumn, summer or winter. This starts to get very complicated, for example, the spring in a cool temperate zone is radically different to spring in a tropical zone, or a high elevation in a sub tropical zone is different to sea level elevation.

In general, I have nothing against nurseries and seed sellers, most of them do a fine service. All I am saying is that it’s very helpful to be armed with some objective unbiased knowledge before you spend your money.

If you have decided to inform yourself before planting, you may consult a planting calendar. There are many to choose from in books, magazines and online. Virtually of these have the same format which is: months, plants and generalised zonal descriptions. They may say, for example, to plant broccoli from March to July (southern hemisphere sub tropical). Broccoli takes about 90 days to grow so if you plant it in March while it’s still warm, it may take a while to get going (or die from the heat and warm season pests) and then if it survives OK, your harvest will be in June.

Whereas if you planted in July, the plant would in the cold time and could easily suffer from the cold and may take longer to grow so it could be ready to harvest in October (120 days) and then be in the heat period. If it spends too much time in the heat period, the flowers of the plant will bolt and you won't get a proper broccoli head.

So then we get into the concept of ideal months to plant or simply OK. Ideal is where the temperature is just right for the whole growing period. Most planting calendars ignore this very important subtly. The other one that is ignored is the impact of climate change. Most planting calendars that rely on broad climate zones use climate data which is an average of a long period of time, possibly up to 100 years. Our climate has become more variable over the last 10 years and it has definitely created more challenges for food gardeners. These challenges can be turned into opportunities with the right knowledge on timing.

On top of that, you may have heard it’s also good to make use of planetary movements when you plant. Growth of plants is strongly impacted by the moon and other planets in our solar system as well as the 12 constellations.

The planting calendar in our Gardener subscriber site addresses the complexities of all the issues discussed above and makes it incredibly simple for you to make an objective choice before spending your time and money on planting. You have 300 food plants (vegetables, herbs, green manure crops, grains, fruit trees and Australian native food plants) to choose from.  Currently we have low level and recent climate information for Australia, USA, New Zealand and the UK.

The bottom line with successful food gardening is to be well informed before you make decisions. It can be a wonderfully rewarding activity so long as your mind is open to learning how plants work and you objectively recognise the impact of forces outside your garden.

Happy gardening

Peter Kearney – www.cityfoodgrowers.com