Replanting and Soil Conditioning

Before you start, you need to look at what is happening underground, especially if you have soil issues (cylindrocarpons, etc.). A replant will not fix any underlying issues in the soil. If a problem is evident, you need to start from the ground up.

Replanting will give you the opportunity to assess and address both your drainage, and any issues with virus and mealy bug. It is also an opportunity to address your soil situation to your best advantage. With a good understanding of what is happening in your subsoils, you can consider deep ripping your vineyard to really condition your entire paddock.

It is recommended to get a soil test done so you can accurately see what is happening and plan accordingly. Soil pits a meter deep will also give you an understanding of what is happening in the sub soils e.g. is it stony and free draining or do you have an impervious layer and water logging.

Although reworking your block is not as effective with silty sandy soils, it would not hurt just to use a tractor with a ripper and just line rip it. If you have stony rocky soil perhaps it is best to totally rework your site. In regards to removing old root systems, old debris will only need to be pulled out in areas of wet feet because of leftover pathogens. This kind of ground needs to be left fallow and planted with a bio-fumigant like mustard seed. Removal of roots would also apply in vineyards that have high level of mealy bug infestation such as in Hawke’s Bay and Gisborne. In Marlborough the Mealy Bug population is considerably lower, therefore any consideration of leaving the ground fallow and attempting to remove as many roots as possible, would have to be a case by case decision. The same can be said for Confidor drenching pre vine removal and post planting in the spring and the following autumn. If the area you are replanting has a number of mealy bug ‘hot spots’, then Confidor drenching would be a good safeguard.

Checklist for replanting

Talk to your wine company in regards to timing.  Can you lift the cap on tonnes per hectare on what you are not replanting to mitigate the cost of having part of your vineyard unproductive?  Probably would only apply if you are replacing less than 10% of any one block, but worth a go!\

• Replanting is the perfect time to re-design your vineyard.  Consider the options and review your overall plan.  If you can make your vineyard more profitable and of higher health and less prone to trunk disease for the next 30 year time frame, why wouldn’t you?
• Ideal scenario: 2.2 meters apart, 1.44 meters between bays, lay down 9 buds per cane and get 20 tonnes per hectare.
• By re-configuring your vineyard, you have the potential to gain an extra third of your overall land area which is ultimately the cheapest way to ‘buy more land.’ 
  if you are considering replanting, stop thinking of the cost of materials and think of what it will cost you to run this vineyard every year after that.  Cost of materials largely irrelevant if compared to operating costs going forward if you choose not to replant.

Do you have any trunk disease or perhaps a mealy bug problem?  If you do, then there are three scenarios and three separate cost anaylsis’ you have to consider:

• To treat
• To replant
• To do nothing  

But what is the cost of doing nothing?  What is the cost of doing it piece by piece and what will it look like in the end?  Consider your net position at the end of 40 years and work backwards. (By comparison, apple growers frequently replant portions of their orchards to remain competitive – don’t be afraid to replant – the benefits will be ongoing.)