With spring now with us, I thought it opportune to discuss some issues that are relevant to this period in the gardening calendar.
Plants expend an enormous amount of energy in spring doing what they do, like flowering and fruiting or extending their size through new growth and now is the time to help them along with some additional nutrients.
There are some fertilisers that can be applied to nearly all plants, like blood and bone, but these don’t have all the nutrients available that are specifically required by a particular group of plants. Native plants are not fond of phosphorus, the for example, whereas roses prefer a fertiliser high in potassium that helps them with lush and healthy blooms. Flowering annuals and vegetables prefer a higher rate of both nitrogen and potassium for both lush foliage and big and healthy flowers.
On the other hand, we have plants that are grown in pots, so care must be taken with the application of fertilisers as plants can be severely affected by incorrect application of fertiliser type. Powdered or granulated fertilisers should never be applied directly to the surface of the soil in the pots as most plants in pots are surface rooting and nutrient burn of these plants can be fatal. Use a slow-release pellets or liquid feed and, again, use fertilisers specific to the plant group. Keep in mind that nutrient depletion in pots is far quicker than for soil grown plants, so the process must be repeated more often to have the plants looking healthy all the time.
For those of us that prefer an organic garden there are many fertilisers now available that are BFA-certified organic. All fertilisers should be well watered in, so the plant has immediate access to the nutrients. If you have mulch down around your plant, rake it back, apply the fertiliser, water in, then replace the mulch around the plant. After the fertilising process has been completed the next important task is to apply either new mulch or to top up older mulch in preparation for the drier months ahead. I have mentioned in previous columns the types of mulches available and these range from shredded cow manure to sugar cane and lucerne mulch and other mulches from trees, like pine bark and eucalypt chips.
The softer mulches like sugar cane and lucerne will decompose over a shorter period than the wood mulches and, therefore, will require more frequent application. They are more beneficial to the soil as they improve the structure and texture of the soil as they break down. Wood mulches will tie up more of the nitrogen in the soil while they are decomposing than the softer mulches, so a keen eye needs to be kept on fertiliser application to ensure the plant is not depleted of this important nutrient. For those of you in high-risk fire areas, a gravel mulch can be used and, although it hasn’t any nutrient value, it doesn’t burn or break down.
Finally, I need to mention the pests that start to invade the garden now the days are starting to warm and the sap is well and truly flowing. Sap-sucking or leaf-eating pests like thrips, aphids and caterpillars should be controlled as they can reduce the vigour of the plants which in turn weakens the plants and allows other pests and diseases to invade.
There are two great control methods that are available to control these pests and they are available now.
The first is a synthetic pyrethrum that is systemic and can be used for the sap-suckers and the other is a control that is derived from beneficial soil bacteria and is useful to control the chewing pests like caterpillars and other leaf eaters.
Call into your local nursery and check out all the new products that are available to make gardening more pleasurable and safer for our environment.
Tilba Nursery, Tilba Tilba