Granary selector is a training 'app' that introduces users to some of the important factors for selecting an appropriate, small grain-store. It also shows how grain postharvest losses can be reduced by adopting a better grain store. 

To operate the app, users must answer several questions about their storage requirements and financial resources. Granary selector will then display a list of the best storage options from a database of 13 store types.

Grain store selection 2

Five of the 13 types of  small grain-store offered by Granary selector

To reveal basic data, the user can selected individual granaries in the list of suggested store types, those not suggested appear in feint text (see the image below).  Much more detailed current information can be seen by clicking on the  ‘Grain stores catalogue' link.

Store selection table

Granary selector is especially useful in cases where households wish to sell a portion of their grain stock to take advantage of seasonal grain price rises to achieve better incomes (for more details click grain price rises). It can also be used to advise those who do not sell grain and are concerned about household food security although their financial resources for investment in grain stores are likely to be more limited.

Using the app is largely intuitive and there are 'tool tips' associated with the slider controls (see image below).  But for more details see the section entitled 'Advice on using Granary selector' below.

Slider advice

Tool tips can be revealed by clicking just above the slider title as shown above


To enter the app click GRANARY SELECTOR  'Storage Investment' tool

Advice on using Granary Selector

Granary selector is divided into two sections: at the top ‘Storage settings’ and below ‘Investment settings’.

You operate the app by moving ‘sliders’ that set the values of different variables. Moving the slider to the right or left increases or decreases the value. Sliders are moved by dragging them using your mouse. If you find that you can’t make a slider move to exactly the right value then you can zoom in to have more control over the settings ('Ctrl +' on your keyboard to zoom in, to zoom out again press 'Ctrl -').

Section 1 - Storage settings

A. Setting grain prices and grain price increases after harvest (for more details click setting grain prices)

Note that although Slider 2 sets a potential grain price increase, the price in some circumstances could also go down, so the the slider can be set to show a negative increase (i.e. decrease).  If you want no increase or decrease be sure to set the slider a 0%. 

Sliders 1 2

 You should set both Sliders 1 and 2 to zero if the household will not sell any grain.

 B. Setting the amount of grain to be stored (for more details click quantity to be stored)

These sliders set the amount to be stored, 1 and 1000kg (Slider 3) and quantities greater than 1 tonne (Slider 4).

 Slider 3 4 new

You may have to use both these sliders. For example 1.5 tonnes would be 500kg on Slider 3 and 1 tonne on Slider 4.

C. Setting grain losses and loss reduction (for more detials click grain losses)

Slider 5 will set the weight loss associated with the current method of storage.  Slider 6 will set the amount of grain loss reduction that would be associated with the adoption of a new store.  For this reason do not set Slider 6 until after you have selected you new store, i.e. until after operating Slider 10.

Sliders 5 6

By setting Sliders 1 to 6, the app calculates the quantity of grain available and its value. These are shown in graphs. The first graph shows the amount of grain to be stored and its expected value at time of sale.

Quantity value new

Graph displaying the quantity and value of the grain stock for sale

 The second graph displays the grain price, the extra profit from storing the grain, and the same profit expressed as profit per tonne. 

Price profit graph new

Graph displaying the grain price and price after storage

A summary table shows information useful to households selling grain since they will be able to see what cash they might have available to repay any loans used for investment in better grain storage. 

Summary of sales new

Section 2 - Investment settings

There are four sliders (sliders 7 - 10) that allow the user to indicate how much cash would be devoted to an improved store. Once the sliders are set then the store types that could be purchased, considering the amount of grain to store and the cost of the store, are listed.

Slider 7 - sets the length of the investment period (months). This is the time over which the costs of better stroage expect to be repaid.  For more details click investment period

Slider 7a





Slider 8  - sets the amount of cash available that can be used as an immediate contribution to the purchase of the store. The more cash that is available the small any loan would have to be. For more details click available cash deposit.

Slider 8a





Slider 9 - sets the amount of cash that would have to be borrowed to help with the purchase of the store. For more details click loan size

Slider 9a





Slider 10 - sets the interest rate on the loan that was set by Slider 9.  For more details click interest rate.

Slider 10a





Below the Slider 10 a summary of financial deatils is presented, as below.  For more details click financial summary

Summary table 2

Selecting the grain store

On the right hand side of Section 2 there is a list of stores. Those that are visible only as feint text are more expensive than the funds available or have greater capacity than the amount of grain to be stored. By changing the settings of Sliders 8 & 9 you can examine how much or how little cash is sufficient to acquire a particular type of store.

Store selection table

 To reveal more details of the suggested stores, you can select individual store types.  To display all the information currently available in the grain store database, click the ‘Grain stores catalogue' link.

Once you have decided which store you wish to investigate further, you should now adjust the postharvest losses (Slider 6) according to the relevant store type. The value to which you should set Slider 6 is shown in the Table below. For more details click on loss reduction.

Losses table b











The information presented in 'Choosing the right grain store' was derived from three sources –

  • An initial survey of storage experts currently developing and extending smallholder granaries (you can download the survey report here),
  • Information taken from the scientific literature, and
  • The experiences of the team developing these pages.

A listing of some of the experts who contributed to the initial survey can be seen in the Acknowledgements.

Pic Brochure1 on ZeroFly Storage Bag English Brochure 1 on ZeroFly Storage Bag (English)


Pic Brochure2 on Zerofly Storage Bag English Brochure 2 on Zerofly Storage Bag (English)


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