School of Life Sciences, JMS Building, University of Sussex, Falmer, Brighton

©2018 by Buzz Club. Logo created by Ross Napier

Garden Shop

calculator

How much does your garden grow?

Getting out in the garden is a great pastime.  With the popularity of ‘growing your own’ on the rise again, many people are increasingly thinking about how to make their gardens and allotments more wildlife-friendly.  There are lots of reasons to make space in your garden for wildlife, and this project looks into the help that those attracted animals provide to our own growing efforts:

Bees (and other pollinating insects) are needed for many of our garden favourites to produce a good harvest, but the impact of insect pollination varies by crop.  E.g. Apples really need pollinators, since their pollen is heavy, doesn’t get wind-distributed well, and the flowers don’t fertilise themselves.  Tomatoes can set fruits without insect help through wind disturbance and self-compatibility, but still produce a greater yield of fruit if well-pollinated by bees.  On the other hand you mostly grow lettuce, or self-pollinating peas, then your garden bees won't have contributed much to the final salad!

The Garden Shop calculator is a simple spreadsheet that helps you to get an idea of:

  1. How much your 'garden shop' (your harvest) would have cost you to buy in a supermarket.

  2. What proportion of that is directly a result of insect pollination.

 

This gives you a clearer picture of how much your garden wildlife help out - and gives us a better understanding of how much UK gardening relies on insects, and how best to encourage people to make space for these important creatures in their green space.

Download it from the link below.  There are instructions in the sheet on how to use it, as well as on this page.

Name:            Garden shopping

Year(s):           2016 -

Focus?           Pollination value

Status?          Open

Results?        Ongoing analysis

Project lead contact:

Dr Linda Birkin

Project summary

2019 results

We had over £1000 of fruit and vegetables grown by Buzz Club members in 2019 (£1600 if organic values are used).

The overall 'bees' contribution was 60% - so insects earned £600 for our members in 2019!

 

Downloading the Garden Shop calculator

The calculator is free to download from the Buzz Club, from the links to the right,.  It is an MS Excel xls. file, so is compatible with MS Office and Google Sheets (and likely any third-party software you use to read / edit xls. files, although it has not been tested out on others).

If you are unable to download the spreadsheet, please let us know, and we can send you a copy of the file, or a google sheets version just for you.

Or you can use the new printable recording sheet to track your harvests, and let us know later to get your calculations!

Let us know if you are taking part in the Garden Shop 🐝

Please note that the file may open in ‘protected view’ when you’ve downloaded it – this is because it has come from an internet location.  This can cause validation errors with newer versions of Office (see the Microsoft Support Page on these errors).

 

The file should be fine, although do give it a quick scan with your virus-checker if you’re uncertain!

 

Save it to your computer to get rid of the error.

You might get one of these warnings at the top of your page, because this is a downloaded file.

Using the Garden Shop calculator

The calculator uses quite broad categories of crops, and the values are based on averages from different varieties.  So apples are divided into 'cooking' and 'eating' apples, but not into different varieties within that (e.g. braeburn and discovery would both just be counted as 'eating').

There are sheets in the file for organic and standard values of produce.  It is up to you which one you use, since you know your own gardening practises best!

To use the calculator, you will need to record how much you have grown of each crop type.  This can be by weight (in grams or ounces) or by number of things. 

 

You can either keep track of your yield overall and put in the total amount of each crop picked (e.g. as 500), or add any sequential harvests (e.g. as =200+300) in to the appropriate spreadsheet cell.

The spreadsheet will do the calculation, and update the small report at the top with:

  • How much it would have cost you to buy that produce in a supermarket *
    = The ‘total crop’ value.
     

  • How much of that value is directly a result of insect pollination **
    = The ‘bee value’ value.
     

  • What percentage of your crop value is directly the result of insect pollination.
    = The '% directly from bees'. ***

* based on online prices from Waitrose, Sainsburys, and Abel & Cole, 2018.
** Pollination requirements of fruit and vegetables are taken primarily from Carreck and Williams (1998), Corbet et al., (1991) and Klein et al., (2007).

*** 'bee' value is really 'insect pollinator value' since insects that are not bees do contribute, but for ease / space, we use 'bee value'!