How to scale City Rooftop Farming

This is a satellite view of a rooftop in Mumbai. This is our farmland.

For this project - we’ll grow only spinach in that farmland.?

Mom Nature’s rules for Spinach

One plant of spinach takes 30 days to be ready for harvest. It grows from seed to harvest and takes 30 days to reach the stage when it can be eaten.?

Using Aquaponics, I have been able to touch 100 gms worth of spinach from one netpot.?

What is a netpot -?

The netpot [1] is a plastic cup that has space for water to flow through.

The netpot can be filled with any medium like coco peat, clay balls or even rock gravel (which is what I use).

The plant sits inside this netpot. And the roots grab onto this medium.?

On our project rooftop - we will install 5000 netpots - meaning we will harvest 500kgs of spinach in a month.?

[ 5000 netpots x 100 gms per month ]

Hold on…

...this is 500 kgs coming to us on day #30. For the rest of the 29 days - no spinach has arrived. And after harvest - it’ll be another 29 days before the next 500kgs will arrive.?

SCALING THE PRODUCTION

We’ll replicate this setup on 30 rooftops in Mumbai.?

But we don’t sow seeds in all the rooftops together. We sequentially stagger the seeding cycle - 1 rooftop each day.?

Sequence of Events

For the first 29 days of this project - nothing happens.?

The first harvest from Rooftop #1 arrives at day #30.

Harvest 2 from Rooftop #2 arrives on day #31

Harvest 3 from rooftop #3 arrives on day #32

...and so on…?

Till day #30.

Now we’re clocking 500kgs of spinach everyday.?

I am selling at a shade over INR1000 per kg. There are 10 cities to scale to.

This is Maths for spinach - a very basic and simple vegetable. Some superfoods like celery are hyper premium because they are difficult to grow in current farming setups !

What’s this 30 day cycle?

This is called a ‘Crop Cycle’ [2] and every plant has its own crop cycle.?

Spinach takes 30 days. Fenugreek takes 20-24 days. Cucumbers will grow in their vegetative stage for about 40 days before they will bear fruit for another 20-30 days - so a total of about 70 days of crop cycle.?

There are indeterminate varieties[3] of plants which can go through a crop cycle many times over - meaning they can continue to supply fruits for as long as a few years. Cherry tomatoes are one of the best examples of such a plant.?

References:

[1] What is a netpot (YouTube video)

[2] What is the Agricultural Cycle?

[3] What is Indeterminate growth ?