Brisbane Local Food

Growing local

With empty rainwater tanks and the offer of a good deal I'm tempting to put in a spear pump.

Bore water comes from underground aquifers and requires a bore water pump, also known as a spear point pump to retrieve the water and it pump to the surface. 

We sit on sand within which there are underground aquifers and many folks around town rely on spear pumps to water their gardens.

How deep is the aquifer? It varies. A neighbor struck water 5 metres down.

Assuming I proceed I'm concerned about the constant recycling of salts on annual plants...Annuals and veges are not the local garden norm. But then since my sand is so porous -- it's a sieve anyway -- management presumes some protocols.

Nonetheless, nurseries exist here because they get free water if they have a bore.

..and monitoring any major changes in pH. Also: keep using tank water to 'dilute' any salt impacts.

But I've always been ambivalent about the option.

Water here pumps up iron salts so it is brownish when it mixes with the air and will leave terracotta colored stains on paths and buildings.

To deal with some of the problems there are workarounds:

  • Use infrequent heavy irrigations.
  • Irrigate at night or early morning to avoid evaporation loss and concentration of salts on leaves.
  • Trickle irrigation is better than overhead spray irrigation.
  • Try not to irrigate in windy weather to get an even distribution.
  • Do not irrigate as a fine mist.
  • Do not water under hot windy conditions.
  • It is important to schedule irrigations based on crop needs using evaporation figures from weather stations, tensiometers or other irrigation scheduling equipment.

These levels are measured as TDS (Total Dissolved Solids). Some examples of salt levels per litre for your information:

  • Rainwater: Under 10 TDS
  • Murray River, in places: 600 TDS
  • Sea Water: 35,000 TDS

Tolerance TDS/mg per Litre:

Ironically I've been fertilizing my garden with (a lot of)  DIY urine and have had no -- touch wood -- salt consequences thus far or so I'm aware of..

If the aquifers were at a shallower depth I'd worry. We are, nonetheless, another sand island like Moreton, Fraser,  the Stradbrokes and Bribie --although we're still attached to the mainland.

Most of Bribie Island sits on two aquifers — a deep one below a layer of rock and a shallow one above it. Rainwater soaks into the shallow aquifer and seeps slowly through until it discharges into the sea at the coastline. Some of the rainwater reaches the deep aquifer and then it moves slowly towards the coast. This effectively stops the seawater surrounding the island from soaking into the aquifers.  

Most domestic bores on Bribie Island tap the shallow aquifer and therefore have the potential to interfere with the natural ecosystems.LINK

One day we'll be another sand  island --  sometimes, albeit briefly,  we are an island.

And finally, from out west we learn:

The application of bore water is a very critical point of the gardening. Probably the best advice is to use as little as possible. Where practical use those plants with a low water requirement or which are adaptable to salty or alkaline conditions. Where other species are required reduce the amount of water needed as much as possible by the use of mulches to reduce the amount of evaporation loss, which in this climate can be enormous. Where there is a need for large amounts of water, it is best supplied at less frequent intervals as it helps to wash the salts down away from the feeder roots. Sprinkling for only a few minutes every day only helps to concentrate the salts in the root zone. A good flood once a week is better than a little each day. Where a drip system is already in use, it is usually better to increase the rate of flow, let the plants have a good water, then turn it off and repeat it in a weeks time... LINK

Views: 2164

Reply to This

Replies to This Discussion

another interesting read Dave - we are also thinking of putting a spear down to supplement rainwater tanks. there is natural spring just a few hundred metres from the edge of our property - an outlet for an aquifer from under D/aigular range . We would only use this in extreme dry - still have 50% tank levels so salt levels would not be such an issue for us  or do we install another tank ...actually thinking of a small one at the highest point so we can gravity feed if the solar power system ever fails so it would be easy to install a larger tank for back up water ! 

The excuse to explore the pump system was very useful. In trying to explain the option I think I vote no.

Any spear pump would be used no more often than once per week. Since there are 52 weeks in a year -- and the need to water the garden weekly will surely be less than that (say x40 hypothetically ) -- I'd still be reliant on tank water and it doesn't take much to do the sums.

Any greater frequency and I'd risk salination.

One spear pump installed to water the garden forty times each year....

I'll review all our past town water bills with that in mind.

Good thinking there, Dave. Doing the homework first often comes up with surprising results. Since we're all paying for the water infrastructure anyway, using some cheap water is a keen idea.

Do you have to obtain a permit in your area to sink a bore Dave.

Not for domestic urban use:MBRC. There are a few local drillers, esp on Bribie.

We went through our water bills with actual usage costs in mind -- and while we are glad the showering daughter moved out -- our shared consumption per person is less than the regional average despite a wee swimming pool and a large veg garden.

Pointing this out to the wife has freed me up from her bill paying paranoia.

This time of year is always dry -- July and August -- although you expect relief in September. The mulch supply dries up. The wind and the high heat worsens what has been a hot and very dry Winter.

One day the rains will come...

And talking of rain, this week looks hopeful. LINK.


1-5 mm not enough to get the juices flowing :-(

Sept 27: over 6 inches so definitely got those juices flowing - mine and the plants!

I have a windmill in the back yard connected to 2 big tanks and a pump down the creek to pump water whenever I need it.  It is lovely water suitable for drinking and whatever I choose.  I'm very fortunate to hit fresh water only 2 metres down.  In the wet season it is only 1 metre.  I live in the Delta of the town Bowen in North Qld.

The soil here is very sandy  though and I struggle to grow fruit trees and veggies etc.  I'd like some advice on how to improve the soil so I didn't have to water my trees and plants every day to keep them moist so they don't die.

Would be willing and able to give me some suggestions to improve the soil please?

Carol check out Dave Riley's many posts. He is on sand and has got good results from different forms of cultivation. Organic matter is the key though, you cannot have too much of it!

I live on beach sand on the coast of Moreton Bay  at the mouth of the Caboolture River. My earth is  yellow and very sterile. Converting it to productive soil has been a hard task.

Most folk here import soil to grow anything other than native plants. But I thought I'd make my own. More fool me.

  1. The first thing I did was throw organic matter at it in the form of mulch. Local mower guys drop off their grass clippings and I use that. I also layer or bury   with newspapers, branch cuttings and cardboard and anything I can get that will break down.Slowly my yellow has gone to grey and then to black. The worms moved in and the variety of plants I could grow increased year by year.
  2. But since it is primarily sandy soil I still have 'perfect' drainage and water flushes though into the aquifers quickly and keenly. I decided I wanted to keep the water near the surface longer  than a short inundation, so I experimented with terracotta clay pots  which hold 2.5 litres which diffuse  their contents over a few days into the surrounding soil.I've also mulched the pathways between the beds thickly in order to delay seepage.
  3. I use trench mulching to hold water near trees: holes filled with paper, manure, coir or whatever that act as a sponge in vicinity of the roots.Similarly, any attempt at tree planting requires the addition of potting mix or imported soil in order to foster the sapling.
  4. Since sandy soil dries out quickly I've deployed a lot of shade to keep it cool and moist. Around here I know which exotic trees grow so I've planted out many frangipanis whose roots don't seem to get in the way of my vegetable making activities.My frangipanis are also deciduous.
  5. Soon after I started this project I decided I wanted to concentrate the best soil I created so I built mounds in my garden -- little hills -- of dug up and raked up earth, and inserted my clay pots in the middle of each so that now my pots are roughly 1.5 litres apart sitting inside hills like volcano craters.I plant out on the contour.
  6. As the years tick over -- 8 so far -- the range of plants that I can sustain have increased and while I use plenty of mulch I've made a conscious decision to close-plant so that I cover the whole patch with growing plants. I also use a lot of groundcovers -- many of which are edible.Some of these I chop and drop for mulch. My presumption is that I want all those roots under the earth interacting with the soil encouraging good microbiology. As it is, I see my vocation as a worm farmer.
  7. Of late I've projected many keen hopes on Vetiver grass which I've planted all over the place. Not only can I harvest the clumps for mulch but I'm hoping I can use Vetiver as a moisture pump since the roots are so deep and fibrous.
  8. Fertilising sandy soil is problematical as anything you use will quickly leach through the granules. I've used manures but I now rely on urine (yes DIY wee) and weed teas I make up from any weed harvest. If I wanted to, I could follow local practice and layer a lot of mushroom compost on/in the soil.Folk here get it from local mushroom farms.
  9. Presently -- even in this drought dry weather -- all I do is top up my pots every two days and squirt some water at recently planted seedlings.My garden is suffering from thirst but it's all alive.
  10. My approach seems to work as I also run another veg garden at the primary school under different soil conditions and I can compare one patch with the other. The school has brought in soil and there is clay content as it borders swamp land. So it holds its waters, although child labour is not reliable as a source for irrigation.

Folk who live in Perth garden on notorious sand  and the habit there is to use bentonite -- a clay -- and mix that with their soil.

As Peter Cundall said in reference to sandy soils: 'If you can garden in Perth, you can garden anywhere'

I'm experimenting with coir (coconut fibre) in the school garden as material inside trenches  -- mixed with manures and newspaper. I've dotted these holes about similar to the way I use my clay pots and placed little red shade cloth hats on them so that they can be engorged with water when hosing.

If I had my time again I'd start off with a Vetiver bioengineering perspective -- and plant as much of the stuff I could as a garden template. In Bowen, with water 1-2 metres down, that should be easy. As it is I expect to harvest a lot of mulch from my Vetiver clumps and plant out many more stems via division.

I've used canna lillies as groundcover mulches and experiment with aloes.I find dog bane very useful and among the edibles, Okinawan and Longevity spinach.

Sandy soil will change over time with focus and effort but don't presume you can grow any and every thing straightaway.On that I'm still waiting.

The alternative route is straightforward: wicking beds...and that's Elaine's specialty.

Ah the human mind!

Methinks -- and I do (often) -- that installing a spear pump is still an option now that I may have access to a very decent price.

A very decent price.

I still need to review the budget but in an attempt to-get-ahead-of-myself I started considering how I would water the garden...

If I assume I'd irrigate once per week with the bore water I turned to Dr Google with a keen eye for hardware alternatives.

I won't be going down the drip irrigation route as I've been there and done that:

As R.L. Tinsley, Inma Irrigation Water Management, & Soil Reclamation Specialist, puts it: “Drip is perhaps the most heavily promoted form of irrigation, particularly by those who do not have to pay for it, operate it, or maintain it.”

We also know that there are supposedly problems with over heard watering especially in the promotion of fungal diseases that wetsies the wee leaves of the planty-poos.

While rain also falls from above it -- apparently -- is not similarly culpable. 

Why is that? Rainwater good:overhead irrigation bad?

But let's assume that aerial water promotes fungal diseases by wetting the leaves...but the sun dries them off. So if you were to deploy over heard irrigation, why not activate it:

  • at night when the wind is down and evaporation is slight
  • in the lead up to dawn so that the morning sun can dry the leaves

Seems reasonable to me. There is much merit in Over Head Irrigation Wisdom (OHIW).

Wobble Tee Sprinkler

But then, doesn't spray irrigation use too much water?

Historically and hypothetically, yes. But the approach has changed with the new technology of emitters. Indeed, some new sprinklers save water and soak so much better than their forbears.

When operated at pressures between 15 and 40 psi, the Wobble-Tee Sprinkler has a very low precipitation rate of 4mm per hour and unmatched evenness of distribution, with an average flow rate of 10 litres per minute.

The Wobble-Tee Sprinkler applies water in a consistently large droplet form, minimising evaporation losses and wind drift, ensuring the water reaches your lawn or garden and not evaporated into the atmosphere. Water is applied slowly and evenly, just like slow soaking rain, preventing puddling and wasteful run off.

Watering for long periods of between 3 and 6 hours allows the soil to be soaked down to the root zone of the plant. Encouraging this type of deep watering will progressively strengthen the plant, which will then require watering less frequently.

Of course offering a good soak was what I'm after -- and the Wobble Tee can be partnered with another low flow sprinkler the Clever Drop. for smaller areas. Of course I'm sure to get wet pathways, but my system treats the paths as water catchment gullies anyway.

These sprinklers are called 'Low Flow' and are part of the new approach to watering from above. (Another example: Lo-Flo)

As for the water I hope to flush through these devices...It's there, below me. I've drunk it. Supposedly has a very low  salt content. I will test it, of course, before any drilling. But i think it's a goer --so long as I keep up with the water from the rain tanks as per my usual gardening habits.To be safe, bore water irrigation should be flushed to prevent salt buildup.

Once/ week come say 4am -- the timer switches on the bore pump for 2-3 hours and Voila! Can do agriculture.

Another advantage with the Wobble Tee fam is that they can be added onto one another so you can localize your irrigation as part of the one session from the same pump or tap.


Important note about adding photos:

Always add photos using the "From my computer" option, even if you are on a mobile phone or other device.


  • Add Photos
  • View All


  • Add Videos
  • View All


Vetiver grass helps to stabilise soil and protects it against erosion.  It can protect against pests and weeds. Vetiver is also used as animal feed. (Wiki.)

GrowVetiver is a plant nursery run by Dave & Keir Riley that harvests and grows Vetiver grass for local community applications and use. It is based in Beachmere, just north of Brisbane, Australia.

Place your business add here! ($5 per month or $25 for 9 months)

Talk to Andy on 0422 022 961.  You can  Pay on this link

© 2020   Created by Andrew Cumberland.   Powered by

Badges  |  Report an Issue  |  Terms of Service