Cost dynamics of maintaining a rooftop Kitchen Garden – Part 2

In the first of this two-part series on setting up and maintaining a kitchen garden, we covered the costs incurred in setting up of a kitchen garden. In this second and last part, we will analyze the cost dynamics of maintaining the kitchen garden.

No of Growing Spaces:
In our previous post, we had covered the concept of growing area vs. floor area. You would remember, that for this specific exercise, we had arrived at a growing area of 295 sq. Ft.

In this specific growing area, we can choose to plant a fixed number of crops depending upon the spacing requirements of the particular plant variety. The no. of growing spaces would indicate the no. of plants that can be planted in the growing area.

Crop Variety:
As the purpose of this exercise is to determine the commercial sustainability of a rooftop kitchen garden maintained by a homemaker or a retired elderly at home, we will consider a conservative scenario.

Instead of painting a rosy picture by using expensive crops like lettuce in these calculations, we will consider a plant with much lesser revenue potential but much higher sustainability potential for a rooftop garden. The crop we will stick with is Spinach. It is widely used in Indian cuisines (and so will have a higher demand and will be easier to sell and use in a common India household kitchen).

Yield Calculations:
Potential Yield per Crop Cycle: In the setup, we have created, the ideal spacing for spinach gives us three growing spaces per sq. Ft. of growing area. Thus, the total number of growing spaces for our scenario is 885 (=295×3). Also, each growing space gave an average yield of approx 200 grams. Thus, the potential yield one would get out of 300 sq. Ft. Kitchen garden would be 177 kgs in one crop cycle.

Yield Spacing:
A point to note is that all of this yield will not mature at the same time. Since we are using Vertical rows (to get more growing area), this results in a lesser amount of sunlight available to the lower rows. So, the plants in the lower racks take longer to be harvest-ready than the plants in the top shelf. This difference in maturity rate is good in a way as it helps in staggering the production and maintaining the demand-supply balance. In our case, the split of 285 sq. Ft of growing area is 145 sq. Ft in the top layer, and 70 sq. Ft each in the middle and lower racks.

Monthly Yield:
Depending upon the nutrition, temperature, weather, and factors like pH, etc. a particular crop’s maturity time may vary and can be controlled to an extent. In the experimental set-up proposed here, we will consider the average maturity times of 6, 7, and 8 weeks respectively for the three levels of growing areas. Considering a month to be four weeks (for simplicity in calculations), 67% of the plants in the top rack, 57% in the middle frame, and 50% in the bottom one will mature every month. This gives us a monthly yield of approx 103 kg per month.

Revenue Potential:
Since the produce grown in your kitchen garden will be super fresh, crisp, soil-free, and free of pesticides, it should command a premium over the one sold by your neighborhood vegetable vendor. Still, without being too ambitious, we will take a price of 25/- per bunch (of 200 gm).

At this price, the monthly revenue potential is at 12,875/-.

Operational Costs:
While calculating the operational costs (or cost of growing the crops) we will consider DWC as the growing technique. The largest cost one would incur in this would be the cost of nutrients. In our experiments, the nutrient needed p.s.f. for one crop cycle of Spinach in DWC is 15 ml (of CityGreens Greens Combo Pack).

From the calculations done above, approx 58% of the growing area will mature each month. So nutrient required each month would be approx 2.5 Liters. At bulk pricing of 1,000 /- per liter, input cost for nutrient will be 2,500/-.

Apart from nutrients, other operational costs would be towards DWC lids, plant holding media (plugs/sponge/net-pots), water, electricity (for air pump), seeds, germination trays, and other sundry items. The cost of the first three of the items listed above (per month) in our experiment stood at 1,948/-. Taking a ball-park buffer cost of 2,002/- additionally towards exigencies, repair, and maintenances, yield differences due to seasonal vagaries, pests, etc., the final input cost per month comes at 6,450/-

Profitability Potential:
Using the above calculations, the profitability potential from such a venture stands at 6,525/- per month for a 300 sq. Ft set-up. This will indicate a time of approx 12 months to recover the Investments.

Points to Note: Couple of critical observations/suggestions:-

Don’t set-up a kitchen garden, if profit is the sole objective – You may argue that 6.5k is a tiny amount for one to go after this business. You will be right. Rooftops are small spaces. The relative capital cost will be high as the benefits of amortization will not kick in for small areas. Also, you would notice that the rental towards land is assumed zero here (the Kitchen Garden is set-up on empty/unused space). Again, the cost of labor is also kept at zero. If you add these two costs, the profit will be meager.

If you do plan to set-up a kitchen garden, go for the right reason. May it be giving healthy and fresh food to your family, or have a hobby or vocation or anything else that attracts you to the greens. Any profit that you generate out of it, take it as an added incentive that helps you to become self-reliant and self-dependent in financial matters (to a limited extent only).

Don’t project Kitchen Garden numbers to decide about commercial farms – Playing devil’s advocate, a Cap Ex recovery tenure of 12 months, profitability potential of 261/- per sq. Ft. Per annum (or 1.13 Cr per annum per acre), isn’t the scenario too good to set-up a commercial farm?

Don’t get into that reasoning. The input costs and running costs in a Commercial farm will be much more and different from a rooftop garden. There would be added charges towards automation, rentals, and labor. Plus, there would be further costs towards marketing the produce, setting up a sales and distribution channel, etc. And after all of that, one may not be able to command a premium price if selling in bulk (to say a wholesaler who will need to add her margin before selling to a retailer, who will add her margin before selling to end-consumer). Take all of those costs into account while thinking of a commercial farm.

No doubt, if done in a correct manner and with the right intent, a commercial farm will make money. But the profits will be reasonable profits and not super normal ones (that you may arrive at by using calculations used in this experiment).

Always remember, if something sounds too good to be true, it probably is.

Gaurav is an entrepreneur whose first Start-up was focused on providing services to patients suffering from Chronic Diseases. While researching about the causes of lifestyle diseases and the ways to reduce their incidence, he chanced upon the idea of growing healthy and nutritious food using advanced farming techniques.

He founded CityGreens with a mission to enable City Dwellers to access Safe, Healthy and Fresh food.

4 thoughts on “Cost dynamics of maintaining a rooftop Kitchen Garden – Part 2

  • Amar says:

    I have commercial complex with 3600 sqft of unused terrace in North Karnataka. Not a windy area but will have extreme high temperature in summers.A shaded poly house will be needed. What do you think the cost to sqft dynamics with this setup ?

    • Nidhi George says:

      Hi Mr Amardeep,
      Thanks for writing in.
      A shaded polyhouse will be helpful especially if you want to cultivate specific crops all throughout the year.
      Cost to sq feet dynamics depends on what you would be expecting in terms of ROI, yield and crop.

      pls, feel free to connect with us on 8310312660 or do share your number with us so that we can reach out to you to be of greater assistance to you.
      Regards
      Team City Greens

  • Farah says:

    Hello!

    I just wanted to know, how many styrofoam boxes & pipes would you need for 300 sq ft?

    • Nidhi George says:

      Hi Farah,
      Pls feel free to call us on 8310312660 .We could then be of better assistance to you.

      Regards
      Team City Greens

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