In our Know your Vines blog series we share practical tips on what metrics to monitor in your vineyard. This is the sixth instalment, stay tuned for more as the seasons unfold! “If you can’t measure it, you can’t improve it.”
Use flower and bunch counts to optimise yield prediction
July is the perfect time for many vineyard owners to do bunch counts, as the grapes are forming. An accurate bunch count gets you about half way there to optimising your yield prediction. Getting your yield prediction as accurate as possible is important for small and medium scale commercial vineyards – it’s a great help for the winemakers to know in advance how much they will have of each type of grape, and how much tank space is likely to be taken up. If you get really good at optimising your yield prediction you can consistently get your prediction accurate to within 5% of your actual yield. It’s well worth it!
Luke Spalding, vineyard manager at Chalk House, told us: “without a good yield prediction it can create a lot of stress for the vineyard team, as harvesting time can get out of control. Importantly, it also creates stress in the winery when you don’t know how much is coming in or when the harvest is going to stop!”.
We’ve come to realise that each year, yield prediction is a journey, a step by step process of optimisation, learning and understanding. With our new Yield Predictor tool it is possible to save and update yield predictions throughout the season as you gather information on your vines. In this part 1 of our yield prediction blogs we will share how to hone your prediction by getting the bunch counts right, and in part 2 we will talk about getting your bunch weights as accurate as possible from lag phase (or veraison) onwards.
First prediction: Inflorescence counts
You may have already started out with a ballpark figure for this year’s yield using inflorescence counts combined with the average weight for each variety-clone block from previous years. This is really easy to do in the Sectormentor Yield Predictor – you just go out and count inflorescences at a number of sample vines out in the vineyard – entering the counts in the app quickly and easily as you go. Then when you log into your account online the Yield Predictor will automatically show you the average inflorescences for each block and the total predicted yield for each block. At this stage you’re working with a fairly crude estimate, but it gets you going!
Second prediction: Bunch counts at flower set
Next, once flower set is complete you can go out and count your bunches, allowing you to see if you have any issues with fruit set (as we talked about here). At this point you can also do your second yield prediction (easy to do in the Sectormentor Yield Predictor) now based on bunch counts — you’re getting closer, and your yield prediction can help you to make a decision on how much you want to thin your grapes (or green harvest).
Thinning the crop is a decision based on craft – you want to optimise yield while ensuring that your not putting strain on the vines. We realise that this is a bit of a balancing act – and this post covers some of the concerns. If you do decide to thin the fruit at this point, you’ll need to go out and do another bunch count afterwards to ensure you know how many bunches you still have. This may feel over the top, but unless you’ve thinned all the vines yourself, it is unreliable to assume exactly the number of bunches you wanted to remove, have actually been removed. The bunch count is the easiest thing to get right, so it’s worth making sure it’s as accurate as possible.
Fine tune your prediction with an updated bunch count after thinning
Every time you do a new bunch count you can do a new yield prediction using the Yield Predictor tool. The tool will automatically update the averages for each new count, as well as remember the bunch weights you entered last time – so it’s really quick to update your prediction and make any minor tweaks! You can also compare your current prediction to predictions you made earlier in the season, to see how the grapes are progressing, and we have a handy graph to show how the total estimated yield has changed, as well as the yield for each individual block.
Everything so far has been about ensuring we get the average number of bunches as accurate as possible. All the estimates have been based on using average bunch weights from previous years – in part 2 of this post we will look at the next steps on the yield estimate journey – getting your estimated bunch weight as accurate as possible for this season. This process starts at the lag phase (just before veraison).