Tuesday 28 June 2011

Garden maths

Middle son had some practical maths yesterday.

He had to work out whether our gardening is cost effective.

There are a few assumptions in these calculations:

-seeds were brought in the 50% sale

-yields were compared with the cheapest non-organic store range which is what we buy. The vegetables we grow are organic in all but certification but he didn't compare with organic prices.

-time was not included

We did not allow for other benefits of growing our own:

-little ones who know that fruit and vegetables don't grow in packets

-satisfaction of growing our own

-organic produce which we would usually not eat

-better taste.

What were his findings?

Rather expensive to grow: tomatoes. In fact, we've made a big loss unless we get a bumper crop which doesn't look likely.

Expensive this year but may recoup costs another year: blackcurrants and raspberries. This was because of the cost of netting. We were given the raspberry canes and the blackcurrants weren't expensive.

Cost effective: garlic

 and basil.
We didn't do a formal calculation for cut and come again salad but I suspect this is also cost effective.

Was this a useful exercise?

Probably, I need to have a careful think about tomatoes for next year. The main costs were the expensive seeds due to previous problems with blight and compost. We do make our own compost but most of this was used on the potatoes so we brought growbags for the tomatoes.

The calculations of yield had to be a bit rough and ready but still worth doing.

Middle son enjoyed his maths which has to be a bonus. He had to work on estimation especially of yields, price per weight and comparing different measurements. Hopefully, he will be able to advise how much of each profitable crop to grow but that is for another day.

This is linked to Frugal Gardening 101.


  1. I agree on the tomatoes this year, we took a large hit and only came up with a very tiny amount.

  2. I find my biggest expense was with the dirt, since I've not got a compost bin, but that should be better next year. I am looking to build one from hardware cloth. Plus I plan to rotate the crops or the dirt since one should not grow potatoes in same dirt. I've also read that one can use pine straw to grow the potatoes in. I will try that next year too, since I can get the straw free. Blessings!

  3. Petra, sorry to be thick but what is pine straw? I'm sure I can't get that but can get free horse manure so perhaps that is another option!

  4. So sorry, we didn't have pine straw in Germany either, we just had pine needles. I think regular straw also may work as long as the first layer is good soil. I don't know about horse manure since the idea behind the straw is to grow cleaner potatoes. I will try straw next year. Blessings!

  5. Hmm, horse manure might not be such a good idea perhaps best for improving the soil in the autumn.