July 2019

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 Everflyht Vineyard, 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.

Yield predictions for different blocks of vines as they progress through the season

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!

Sectormentor Yield Predictor tool using flower counts

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).

Check out 10 key metrics to monitor in your vineyard and find out how our app Sectormentor for Vines helps you record data & manage your vines for the best quality grapes.

In our Know your Vines blog series we will share practical tips on which metrics to monitor in your vineyard. This is the fifth instalment, stay tuned for more as the coming seasons unfold!

“If you can’t measure it, you can’t improve it.”

The value of knowing % Fruit Set

After the buds have burst, flowering is over (or almost over)…the caps are off and the grapes are beginning to form – we are well and truly into another season and the countdown to harvest has begun, yet again! In this post, we wanted to tell you a bit about % fruit set and why this a useful metric. If you did an inflorescence count prior to flowering then it’s very easy to determine what % of your inflorescences have “set” fruit.

Photo: Vines just finished flowering – fruit set just starting…

Fruit set is vital in the phenological progression of the vine, as it is the moment that the fruit actually comes into being -it’s the first indicator of how abundant (or not) the harvest might be. Knowing the % fruit set helps you to know if the vine is out of balance or if something went wrong at this point and you need to do things differently in future years.

Of course, a key factor that affects fruit set is outside of our control – the weather! High winds and heavy rain (or worse, frost), can really damage flowers’ ability to turn into fruit. But poor management decisions, as well as reduced vine health, can also impact fruit set – so this is an indicator to learn how to learn from!

“We monitor fruit set to make sure we are managing the vineyard as effectively as possible. You have to be very careful during flowering, especially with any sprays, it can be very delicate and you can cause poor fruit set. So we always check % fruit set to learn and improve our management in following years.” – Joel Jorgensen

Poor fruit set in vines can be due to carbohydrate supply, water supply and mineral imbalance. Here is a nice description of how and why from a US vineyard outreach officer:

‘Deficiencies of any of the essential mineral nutrients (e.g Zinc, Boron) can affect fruit set detrimentally.  Unbalanced C:N status of the vine can also result in poor flower development and fruit set. Overly vigorous (lower C:N ratio) or weak vines (higher C:N ratio) with insufficient or in-efficient leaf area (e.g. due to herbicide damage, insect feeding, disease attack)  tend to have reduced fruit set and loose clusters.’ (Reference)

Different varieties can also be more or less likely to set all their fruit, so starting to understand different varietal and block behaviours with fruit set helps to build up a picture of those vines over time and optimise vineyard management based on the expected fruit set. This also means you can pay special attention to any areas of the vineyard that are particularly susceptible at flowering:

“Flower set is dependent on the weather but some varieties are more prone to poor fruit set in certain conditions. When we count inflorescences, we assume 100% fruit set. In August when we count bunches post flowering we then update the yield prediction. And also determine the % fruit set so we can manage the blocks accordingly going foward.” – Will Davenport, Davenport Vineyards.

How to calculate fruit set?

Go out and do an inflorescence count as the flowers come into bloom. Then sometime after flowering is all finished, and the caps have blown off, go out and count the number of bunches. ‘No. of bunches’ divided by the ‘No. of inflorescences’ will give you the % fruit set. Using Sectormentor makes this easy:

Monitoring with Sectormentor:
Sectormentor makes it easy to record flower / inflorescence counts and bunch counts at the touch of a button on your phone out in the vineyard. All the information you record is then available as soon as you get back to the office. You can easily see the % fruit set for each block, and this is recorded year on year, so you can start to build up a picture of each block and how the fruit sets for that specific clone, variety, location. This is about really knowing your vines!

Check out 10 key metrics to monitor in your vineyard and find out how our app Sectormentor helps you record data & manage your vines to build ecology, profitability and beauty for your vineyard.