Sunday, 20 September 2015

Benefit Cost analysis of growing vegetables in the backyard

People often tell me that growing vegetables costs too much, or that they are cheaper to buy from the shops, my reply to them is "you are doing it wrong".

Growing vegetables will save you money.  If you are spending more than you save you are doing something wrong.  Grow some food, it will save you money. 

If you have a back yard you should grow some vegetables.  I grow and eat plenty of things that I could never afford to buy.  It is simple and it will save you some money.  I will tell you how I used to grow vegetables cheaply in suburbia with limited space and give you an idea of how much money it saved us.
Heirloom tomatoes - one day's harvest

Growing Vegetables in the backyard to save money

When we first bought a house with a small yard I put in a small vegetable garden, I sat and thought before each purchase as I wanted to save money.  I tried to make sure that everything I bought would return the investment in 3 or less years, if anything would not return that investment I asked myself if I really wanted it.  Sometimes the answer was still yes.  Why did I choose 3 years, I can't remember, it is just the rule that I go by when making purchases.

When I was about to start that garden I looked for something to make it from for free.  We had a sandpit in the lawn left behind by the previous owner, I dug out the sleepers and used them as the vegetable garden edging.  I dug over a section of lawn that was out of the way, put in the sleepers as edging, and included some of the old sandpit sand to improve the drainage.  It cost me time which I otherwise would have spent in front of the television, and I bought a cheap spade and wheelbarrow (which I needed to buy for other projects), but other than that it was free up to this point.

I needed to buy some vegetable seeds or seedlings to plant, this was my first real cost.  I decided seeds were cheaper than seedlings and offer the best return on my investment.  A packet of tomato seedlings costs about the same as a single tomato plant and can be used to grow many tomato plants over several years.  I also decided that any seeds I bought must be of things that I could grow out and save seed from each year or of something perennial that would not need replacing each year.  This makes seed buying a once off expenditure so even if they never break even they will still be providing me food for years to come.  At that stage I had no intention of ever selling seeds or breeding my own superior varieties, I was only planning on saving a little money by growing vegetables in my spare time.  Saving seeds lowers costs dramatically, you should save some seeds for yourself.

I normally don't include costs and things in blog posts as they vary from place to place, but to demonstrate how growing vegetables in the backyard is far cheaper than buying them from a shop I am going to include some dollar amounts here.  I am also going to try and be realistic and include things where you may lose money.
Yellow pear tomato, seeds are cheap and yields are high

Benefit/Cost comparisons of growing vegetables in the backyard versus buying vegetables

I payed $3 for a packet of tomato seeds so I wanted to get at least $3 of tomatoes in less than 3 years.  That was my goal, everything had to break even within 3 years.  I can't remember how much each plant produced, or how many plants I grew that first year, but all together they returned about 12 kg of fresh tomatoes.  According to this site one kilogram of tomatoes costs about $5.  Not surprisingly one single tomato plant returned a lot more than $3 worth of tomatoes in a single season.  I am not talking organic gourmet tomato prices (even though I grow everything organically and I probably have what is considered gourmet varieties), I always calculate using the cheapest vegetable I can find.  I then saved seeds from those tomatoes and actually still have that variety today.  That was 12kg of tomatoes the first year for $3.  Already, with that one purchase of tomato seeds, I had lowered the costs of my fruit/vegetables a tiny bit.  I was already ahead.  We were already saving money by growing vegetables.

If you are not breaking even in under 3 years you are doing something wrong, perhaps you are growing the wrong variety or perhaps tomatoes or whatever it is are not suited to your climate and you should grow something else.

When I payed $7.50 for a kilogram of seed potato that first year I wanted to get at least $7.50 worth of potatoes in under 3 years.  The first year that 1kg of seed potatoes returned 20kg of good sized potatoes plus a few kg of smaller ones that I saved to plant the following year, the second year they only grew 15kg of large potatoes plus some to save, the third year they yield 8kg.  That's right, I keep pointlessly accurate records of things like this.  So for an initial $7 investment I got 43kg of potatoes over 3 years, not too bad.  Again, if you are not at least breaking even you are doing something wrong.  The average price of potatoes is around $3.78 per kg, so around 2kg breaks even.  The $7.50 for seed potatoes was well worth the investment especially considering the 20kg return the first year.  It is not difficult to save money by growing your own food in a small backyard garden.

That first year we spent $10.50 on tomato seeds and seed potatoes and ate around  $135.60 worth of fresh produce.  It is not difficult to see how much money can be saved by growing a few vegetables at home.
Perennial leeks, plant once harvest forever
We grew a few other things that first year, almost all of them returned far more than I payed for them.  Beans and snow peas grew tremendously well that year and I saved seed to grow in following years.  As well as providing a delicious crop, being legumes they also sequestered nitrogen from the air and made the soil more fertile and productive which was an added bonus.

Some seeds I bought did not provide great yields in that tiny vegetable garden.  It is important to know that this is going to happen too.

I bought multi coloured carrot seed, they grew well but when carrots cost $0.65 per kg I did not get $3 worth of carrots out of them that first year due to lack of space.  I probably got about 50 cents worth of carrots.  I saved some of their seed and planted the following years, to be honest I don't think I ever got $3 worth of carrots from them and should have probably stopped growing them.  You need to grow a lot to break even when they cost so little from the shops.  Space was the limiting factor there.  I was not saving money by growing carrots so I stopped growing them and used the garden space for more productive and worthwhile crops.

I bought an apple tree in our second year to plant by the fence, after counting and weighing the apples that we ate from that tree (I can't help but to weigh, measure and record certain things) and factoring in the cost of apples of the same variety from the shops I found that I broke even part way through the second year.  There is no point using the cost of organic apples as I would not buy them, I would buy the cheaper ones.  

I was also given some strawberry plants which performed wonderfully, it is difficult to work out how much they saved us as I would never buy strawberries because they are too expensive and do not taste very good.  These plants did replace other "afternoon tea" and "dessert" type foods so actually did save us a decent amount of money.  Considering that they cost me nothing to begin with I was more than pleased.
Herbs are worth growing, but they probably don't save you money
I also bought some herbs, this is where costing got even trickier.  Normally I would never buy fresh herbs as they are too expensive, so no matter how productive the plants were they would never truly break even.  This is ok when you factor it in with other things that actually did lower costs.  It is good to know that there will be things that are worth growing that will never break even, it is wise to make informed decisions about such things.  Lets be honest here, growing ornamental flowers never breaks even yet they are a multi-million dollar industry in Australia.  I think growing a few herbs is a great idea as they taste great, it should be a once off purchase as many herbs are perennial and it is simple to save seed from most annual herbs.

Then I bought some things that I had never seen in the shops, things like yacon.  I figured this was dead money as it was not replacing anything I would (or even could) buy.  I was willing to proceed as everything else had grown so well and lowered costs.  The trick here is not to ensure that each individual plant breaks even, but to make sure if something will lose money that you are aware of it before hand and have accounted for it somewhere else.  

The yacon grew amazingly well, the kids and I love to eat it.  It had saved us no money as it was not even replacing some other fruit or vegetable.  Yacon roots secrete sugars into the soil and attract and feed beneficial soil life such as earth worms.  Everything that grows near yacon seems to be larger and healthier, so it probably does save us money in some way that is too difficult to calculate.  Yacon is a perennial vegetable and I still have that same yacon growing today, it is one of my all time favourite vegetables.  I believe it was money well spent.

Production costs of growing vegetables in a small suburban backyard

People often complain about all the 'hidden' costs which I have conveniently ignored so far, what about fertilisers, pesticides, herbicides, water and most importantly time?  Again I say if you are not saving money by growing vegetables then you are doing it wrong.  Lets look at these hidden costs.

People often complain about the cost of fertilisers when growing their own food, I have never used them.  You don't need to use them in a backyard, it is cheaper not to.

When we lived in town I would compost the lawn clippings as well as tea bags, egg shells and whatever vegetable scraps we had and use that as fertiliser.  It was virtually free as we were using an otherwise wasted resource and the vegetables grew tremendously well with that as the only fertiliser. The soil got richer and more fertile each year, this cost us nothing.

After a while we got chickens and also used their manure and bedding as fertiliser.  Someone gave us their old guinea pig, this little guy worked tirelessly eating weeds/grass and turning that into manure.  He lived a long life with us, reaching a ripe old age of about 7 eating nothing but grass and weeds and producing high quality fertiliser for us.  I miss him, he was a hard worker and a placid friend for my children.

There is no need to spend money on fertiliser as you will have something around that you can use for free.  I can understand large acreage buying fertilisers, but if you are spending money on fertiliser in town you are doing it wrong.
Chickens, a great source of manure (don't worry they did not live like this for more than a few minutes, we were only carrying them from the incubator to the brooder and this tiny box was the safest and easiest way)
People often complain about pesticide costs, again I have never used them.  If a plant gets hammered by insects then perhaps I should grow something else.  There is no point beating a dead horse, sometimes it is wiser to cut your losses and grow something else. 

Some pests can be beaten using other means, others sadly can not.  Cabbage white butterflies for example do not like to like to lay eggs where there are a lot of other white butterflies.  I tie some string running along the length of the bed next to the brassicas.  I then cut white plastic bags into small rectangles and tie them in their middle along the string.  The end result looks like a heap of butterflies fluttering along the crop in the wind.  Don't be fooled,  this does not eliminate the pests, but it does reduce them to a sensible number.  We went from several dozen caterpillars per leaf of every plant, which I was removing each day, to only 1 or 2 per entire row of plants.  This cost me a little time, an old plastic bag and a length of old string that I found in the garage. 

I keep slugs and snails away from seedlings by surrounding them with crushed egg shells.  Apparently the slugs/snails find them too sharp and do not go over them.  This has to be reapplied every now and again as birds or something steal the pieces of shell.  Egg shell is virtually free, my chickens and ducks lay eggs which we eat or hatch and I use the shells either in compost or to protect seedlings.
Crushed egg shells protect seedlings from slugs and snails

People ask me "what about weeds and weed control?".  In a back yard you should not have weed trouble that you can not dig out easily enough.  Large scale broad acre farms may be different, but in a back yard if you can not dig out a weed something has gone wrong.

If you have chickens or guinea pigs they can be put on a vegetable plot between crops to eat out weeds and fertilise the soil for you.  Chickens can be very destructive in the vegetable garden so I would only use them between crops and I would be careful they do not scratch all the soil out of your garden.

I don't see the point of using a herbicide in a small backyard vegetable garden.  If you do not have chickens or guinea pigs then pull out the weeds yourself, don't spray them.  If you can not pull out the weeds yourself due to ill health or something consider mulching heavily with newspaper or something.  People will give you piles of newspaper for free if you ask.

People often drone on and on about how much they will spend in water if they grow vegetables, in a small backyard this is not the case.  When we lived in town water cost $0.55 per kiloliter, I don't know how many thousand liters I would have used watering my tiny patch but all up it would have added up to maybe a few dollars each year.

The cost of water is undoubtedly a lot higher these days and would certainly vary from town to town, even so you would probably be looking at the cost over an entire year in single digits.  This is not a large cost and can easily be factored in to a productive vegetable garden.  There is certainly no point complaining about such a small cost each year when the financial benefits are so great.
Duck potatoes growing in a bucket.  Water is cheap, duck potatoes are expensive
I can not put a dollar amount on your time, I also can't tell you how long you will spend gardening each week or total over a year.  This will depend on how much time you are willing to spend out there.

People often talk about how gardening is great exercise and excellent for good health.  Others tell me that they find gardening therapeutic.  Some people claim that the clean, organic, nutrient dense food they produce will save them medical costs, doctor visits and give them greater quality of life when they are older and less sick.  I don't know about this so can not comment.

I can't tell you the benefit/cost ratio regarding time in growing your own food in the backyard.  I don't know anything about that, but I do often think perhaps my time is better spent growing my own food rather than working so that I can pay someone else to grow it for me.  When we lived in town the time I spent in the garden was just time I otherwise would have spent in front of the TV.

I can grow a lot of things that I can not buy in the shops, and I can grow other things that are best fresh.  Some things such as sweet corn only taste their best when eaten within 15 minutes of being picked.  After that the sugars convert to starch and you lose a great deal of quality.  The time it takes to drive home with your 'fresh' corn from the shops is enough to stop it tasting its best.  I find that the small amount of time required to grow corn is more than worth it when it tastes so good.
Sorrel, you don't find this at the shops
Yacon, more than worth a little time to grow this at home

How much food can you produce in an average backyard?

Back in the old days most people grew most of what they ate, but back then life was easier and the world was a vastly different place.  House blocks were generally a lot larger and people had a great deal more spare time, it was quite rare for both husband and wife to have payed employment outside of the house.  Producing meat in your backyard was seen as pretty normal back then, today if you even consider butchering a chicken you would be frowned upon.  Back then people rarely bought much food, unfortunately times have changed.

If you wanted to you could probably produce all of your fruit and vegetables in your yard, but few of us have the time, the space or the inclination to do that.  Your yard would no longer be useful for anything other than producing food.  You are better off just growing some things that you like, still having a pretty normal looking yard that is still functional, and saving a heap of money along the way.  A 1m by 4m plot along the fence can be tremendously productive.
When we were in town we had two vegetable plots which were just under 2m x 2m, about 7.5 square meters together.  That small amount of land produced about 10% of our vegetables.  For 5 weeks each year we did not buy vegetables at all, then we got a few handfuls of vegetables throughout the rest of the year.  You can see how such a small amount of land can save you rather a lot of money.

I personally think that if you are not saving money by growing food then you are doing it wrong!  If you have tried and things are not going well talk to someone who may be able to help.  Just like the carrot example above you may need to change your plant choices.

Where to get heirloom vegetable seeds and perennial vegetables

There are many places that sell seeds and perennial vegetables.  Whenever buying please look at things that will either be perennial and grow for multiple years, or things that you may be able to save seeds from.  By doing this you will lower your costs as they will be a once off purchase.  Some things will be too difficult or time consuming to save seeds, that is ok too as long as you are aware of it and are saving seeds from other things.  Try to pick varieties that are different from what you can buy, many varieties that are available in shops are excellent for large scale farming and distributing over large distances but are not great for home gardens.  The aims of a home vegetable garden are different to that of a broad acre monoculture.

I sell some perennial vegetables and heirloom vegetable seeds through my for sale page and can post at cost to most of mainland Australia (not Tasmania or WA).  There are many other good small home seed sellers, as well as some larger ones that are good.  If you deal with the smaller family run seed sellers they are more likely to offer advice if something goes wrong as well as give you fresher seeds.  One of the largest and most well known heirloom seed sellers in Australia is dreadful, and ebay is very hit and miss, so do some research prior to buying anything.

You have little to lose and a lot to gain, grow some vegetables and save some money.

1 Thessalonians 4:11 and to make it your ambition to lead a quiet life: You should mind your own business and work with your hands, just as we told you,


  1. I have just read about an experiment that shows that crushed eggshells apparently do not protect seedlings from slugs and snails. I have used egg shells for years and have had good success but that may have been luck. After we have moved and settled in a bit I plan to repeat the experiment to confirm or deny it. I will write the results here.

  2. Mulching with 5cm(2inch) straw will help too, better if it is chopped in 2cm(~1inch) pieces.
    Hello from Lithuania (Europe) :)