Frequently Asked Questions
Sometimes demand is high, and driving isn't much fun, so we prefer areas not too far from our Brunswick base (in Melbourne, Victoria, Australia). That means we prefer the inner north, west and inner south of Melbourne, but we also frequent the outer north and west. We'll always venture further away if the project is one we're keen on, or there's a bit of a lull in work, so it cant hurt to ask!
Firstly, wicking beds are best suited to veggies. They aren’t generally used for trees and other perennial plants although you might have a few strawberries and other shallow rooted perennials in there. Most veggies do better in wicking beds because of the low stress, constant moisture. Some root crops, like garlic might be prone to rot in these conditions however although we've not had problems! And your daikon radish might not develop to a full size due to the shallow (generally 35cm or less) soil layer.
The crucial height to line to is at least the height of the overflow pipe. Any extra than that, and the plastic isn't being used as a water reservoir. That said, when we do wicking bed installations, we line our beds almost all the way to the top of the bed. While that's not necessary, extra liner increases the life span of the timber.
Our Custom Wicking Bed Conversion Kit Calculator will give you enough liner to go all the way to the top of your bed just like we do. This also gives you a little extra to play with when installing, so less can go wrong. If you check out our standard sized kits (Wicking Bed Conversion Kit: Small and Wicking Bed Conversion Kit: Large) we mention the maximum sized bed you can do with our kits. In this case the liner will go to within 10cm of the top of the bed. So if you didn't line it this high, you could create an even larger bed.
In the VEG wicking system, when the water reservoir is full, the water touches the geo-textile, and creating a wet blanket, and is sucked up into the soil via capillary action.
The screenings themselves actually wick water upward to a certain extent, thus contacting the geotextile fabric and wetting the blanket, even after the water level has dropped below full. In our research we have observed the wicking effect up the screenings themselves to be up to 10cm:
We use a specific kind of gravel – 7mm bluestone screenings or 1/4 (inch) minus in the old tongue – for three reasons:
1) it is inert or close enough to it so won’t decompose, therefore it will
2) hold up the soil! and
3) still have enough room between the pieces for lots of water.
To round it all out, the enclosed nature of the wicking reservoir, regardless of how much or how little water is retained, creates conditions for humidity and condensation to occur (especially in warm weather when the plants most need that moisture). We don’t know if this has been studied or not, but it does help explain why the plants in our wicking beds remain happy even as the water level drops below the extent to which the screenings may wick water up to the geotextile fabric. We think water, even from the lower reaches of the reservoir, condenses on the underside of the geotextile fabric, then wicks up the standard height (30-40cm) into soil. Hence the fact that the many beds we build in this way all work so well.
Our liner is certified potable-water grade and especially produced to line the likes of public drinking water reservoirs. It's also tough and hard to accidentally puncture when installing. You can read more about it here.
Timber products we can deliver within Melbourne, and wicking conversion kits we can send to most of Australia. Costs will be calculated in the shopping cart long so you can see them, and start from $15.50 for wicking kits. You can either add what you want to your cart and see the calculation, or read more about shipping here.