Monday, 12 May 2014

Observing how nature waters the garden and the difference it makes

Observing how nature waters the garden 

Having observed how well all the plants grew last week when we had the first proper amount of rain for a fair while I was wondering why the plants didn't grow as well the week before when I watered them myself.

5 possible reasons came to mind for the difference in growth between the 2 weeks.
1) I didn't water enough
2) Last week's temperatures weren't as good
3) The amount of sunlight was less
4) The rain water was evenly spread over 7 days rather than 1 big watering session as I do 
5) A mixture of water,light and temperature.

Looking at each one in turn and comparing the 2 weeks:-

One veg patch is 3m x 3m in size and over the last 7 days we have had 12mm of rain in the last week so I can calculate the amount of rain that fell on that patch. 

(3m x 3m x (12mm/1000)m) x 1000 = 108 cubic litres or 23.75 Cubic Gallons

I work in gallons so I'll use that.

23.75 Gallons of water fell on that one small veg patch during the week.  That's a lot. A big watering can is 2 gallons and a mid size one is 1 gallon. So between 12 and 24 watering cans of water went onto a 3 x 3 metre bed. For a start there is no way I would have put that much water onto such a small bed as it seems a ridiculous amount of water to use plus I don't have time to or the energy to put at least 12 big watering cans of water onto 9 square metres of veg...but clearly that is the right amount of water to give the plants, at least it is once at this time of year since that is what nature has done and that is when the plants grew well.

Next I need to know how much water I did actually water them to make a comparison, but I did it with a hose pipe and I can't remember how long a sprayed water for. The next step is to time how long it takes to fill a watering can using the hose pipe with the same spray (which is not the same as raw water coming out of a hose pipe because the end lets less water out so that the pressure builds up to spray it further).

Time taken to fill a 1 gallon watering can was 45 seconds using the same hosepipe spray attachment. I just stood and watered the same patch with the hose and timed that to see how long I take to water that bed. 2.5 minutes. 2.5 minutes / 45 seconds = 3.3 gallons of water.

2.5 minutes of standing there watering seems like an age, it also seemed and looked like I was giving the plants a dammed good soaking but you can see in reality when nature waters the garden it uses a huge amount of water compared to you. If I was to water that same bed by the same amount that nature did I would have had to spend 18 minutes watering with the hose pipe!

The next thing to do, which I won't, is to measure the moisture content and see how deep the 24 gallons over a week penetrates compared to 3.3 gallons. In reality my watering is probably only penetrating the top 2 or 3 inches if that of soil where nature probably watered the top 8 to 12 inches.

If you look at the root system of plants there are very few roots in the top 3 inches compared to 6 to 12 inches. My watering is probably doing little more than keeping the plants alive compared to nature's watering which is really feeding the plants and hence the difference in growth.

As for the other points, the temperature was similar and the amount of light was less on the week of rain because of the clouds.

Clearly, observing nature can help grow vegetables and I conclude that at this time of the year, even if it is only one week then what the plants need is the same amount of watering I give them but EVERY DAY for 1 week. I need to spend 18 minutes spread over 7 days on that one patch just watering. Scale that up by a factor of 10 to cover the rest of the veg patches and I need to water 240 gallons of water spread over 1 week taking a minimum of 3 hours!!!

I need to find a better and more efficient watering system if I am to reproduce nature's watering system during dry spells at this time of the year. That is 5 full water butts for just 1 weeks watering. I'm presuming my butts are 50 gallon but they could be half since I haven't measured them.

Harvesting rain water that falls on our roof so that I can use it when needed (dry spell) becomes a priority but to save time I need an irrigation system because I don't have 3 hours a week (even if it is just for a few weeks of the year).

It may seem like a huge amount of effort to calculate and work out what nature does but I think it is necessary to fulfil the "observe" part of permaculture, at least for some of us, others can just learn from my effort, but someone has to look deeply into things to gain a better understanding.

We all observed how well and how fast the plants have grown over the last week but with climate change happening and our weather being more extreme are we ready for dry spells, and the corresponding extreme wet spells? Dry spells hold back and kill plants, wet spells can drown plants so we need to know what works best, drain better during very wet spells or protect the plants from over watering and water the plants to mimic nature's good work during the extreme dry spells. You can't do this without harvesting water and then using it during the dry spells. (Unless you are happy to use processed water from a tap needlessly).

Question is, what's the best watering system that I can put into place? To water the whole veg patch in one week, it is unreasonable to think that I can fill 240 watering cans (5 hrs + just to fill cans plus the walking and pouring time) or spend 3 hours with a hose pipe. Some people use a water sprinkler on the end of the hose pipe but why pay for that amount of water or waste processed water when you can use rain water?


  1. I have always wondered if it was anything to do with the nature of rainwater as opposed to tap water that has such a noticeable effect on plants (notwithstanding that nature delivers a lot more quantity as well).

  2. Some of the plants get watered from the rainwater in the water butt and it doesn't seem on the face of it to make a noticeable difference. That's not to say there isn't a difference but quantity seemed to be the difference, or at least the majority of the difference in this particular instance.

    Perhaps worth a test during the next dry spell to heavily water half the same bed with rainwater from the butt and the other half from the tap.