Term 3 – Week 8 – Weed Spraying & Shelter


Alders creating a shelter belt

Shelter belts can be an effective way to protect crops from wind damage and make the conditions much more pleasant to work in! Also, wind can decrease temperatures leading to fewer growing degree days. Shelter works by filtering wind through the trees, slowing it down and deflecting it.


There are heaps of different plant species that are options to use for shelter belts. We went to see a few examples around the Cromwell area. Lots of them are just pine trees. The one I really liked used lots of native plants, but it would have been considerably more expensive and time consuming to plant than just a row of pine…


Shelter belt using native plants


To prepare a new site for a shelter belt planting the soil needs to be ripped to allow the roots to penetrate, irrigation needs to be installed and weeds need to be controlled. Plantings would usually be done in spring or early autumn. Bare root trees are only available in spring. The best advice for planting trees is to dig a much wider hole than you think you’ll need and score the sides so the roots don’t end up girdling (roots strangling themselves).


Example of root girdling – yikes! 

Water the hole before planting and water thoroughly after planting. You can use some fertiliser but it is best to be conservative with application. Blood and bone is a good option. If the weather is dry they will need to be watered once a weed during their first season. A heavy watering once a week is more effective than frequent light watering. You could also consider using a mulch to conserve water.

Back to weeds!


Nice outfit April!

This week we put our weed spraying plans into action. The weather conditions on Wednesday were probably as good as it gets. No wind or rain.

We sprayed under the vines, along the herbicide strip, using a knapsack sprayer filled with 15L water, 120ml glyphosate (Round Up) and 25ml Burn Off (additive to help with rain-fastness). Spraying the weeds at this time of year will help protect the vines from frost damage. Weeds radiate heat out at night cooling the air around them. Getting rid of them and mowing the swarth in-between rows helps keeps frost at ground level below the vines. The temperature difference between ground level and vines could be a couple of degrees.

Spraying with glyphosate needs to be done pre-bud burst since it is a systemic herbicide. The trunks of these vines are old enough to use it without damage but if it comes into contact with buds or leafs it would be taken up by the plant and move into the roots. For summer weed control you would need to use a non-systemic herbicide like glyphosinate that only kills what it comes into contact with, if it only touches the leaf only the leaf will die. It doesn’t move through the plant like glyphosate.

Some of the worst weeds in a vineyard are fathen, stinging nettle, mallow, couch and clover. They have hardy root systems that make them hard to kill. Couch is one of the worst since it spreads by rhizomes root system. Even one tiny bit of root left in the soil will regrow. These weeds are all pretty vigorous and compete with the vines for resources such as nutrients, space, light and water.


Knapsack sprayer about to begin murdering some unsuspecting weeds

In propagation class we continued preparations for the October plant sale. All the seedlings are really coming along.


Tray after tray of tomato seedlings

We also had our first go at cuttings! We took them from a hedge at the polytech. You take a cutting that’s about as tall as your hand, cut it off at a node, cut off all but the top two leafs, cut them in half, dip the stem in hormone and stick it into the tray (50% potting mix and 50% pumice). There should be some new roots growing in about a month.


Broadleaf cuttings

Last week’s weather:



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