I have felt guilty for a long time about having a raised vegetable bed at the back of my property (that the previous owners installed), but only using it for grass clippings.
After months of “encouragement” from both sides of the family we finally agreed to get into it.
I was a little shocked at the pricetag of the first trip to a garden centre at about $80 and wondered even then if we were going to get a return on investment.
Here’s is a break down of our expenses and our harvest over the 3 month period.
Expenses
- Bag of Compost: $20
- Pots: $20
- Seedlings: $3 x 15 = $45
- Pesticides: $6 x 3 = $18
- Water: 300 litres x 90 days = 27 m3 (27,000 litres) @ $1.24/m3 = $30
Total: $133.00
Harvest
- Bok choy x 9. Value each $3 x 9 = $24
- Lettuce x 5. Value each $3 x 5 = $15
- Brocolli x 2. Value each $3 x 2 = $6
- Cabbage x 2. Value each $3 x 2 = $6
- Potatoes x 1.5kg. Value $5
- Silverbeet/Spinach x 2. Value each $2 x 2 = $4
- Cauliflower x 1. Value each $3 x 1 = $3
- Beans x 150grms. Value $0.50
Total: $63.50
Return on investment = $63.50 – $133.00 = -$69.50
Conclusion
Backyard Vegetable Gardens of this size are not viable based purely on the expenses and harvest, without taking into account the opportunity cost of the labour component, which can be calculated as follows:
Labour
- Watering: 20mins/day x 60 days
- Sewing/harvesting: 60mins x 10 days
Total: 1800mins = 30 hours @ $100/hour = $3,000