How to fill gaps and seal Maricopa untreaded timber garden bed?

[diybaby]

Help! We have finished building veggie beds. We used untreated wood - what should we use to fix gaps and cracks in the rough sawn spaces and what should we do to oil / seal the beds. Needs to be food safe :-))) 

 

 

[MitchellMc]

Welcome to the Bunnings Workshop community @diybaby. It's sensational to have you join us, and many thanks for your question about creating veggie beds.

To seal gaps in untreated wood for veggie beds, start with a sealant like Sikaflex 11FC, which is durable, flexible, and food-safe once cured. It’s a good choice for filling cracks and gaps in rough-sawn timber as it forms a waterproof bond and prevents dirt and moisture from getting trapped. Apply this on the inside.

Once you've filled any gaps, a food-safe oil or sealant will help protect the wood. For this, I’d recommend pure linseed oil (not boiled linseed oil, which often contains additives). It penetrates the wood, offering some moisture resistance and extending its lifespan. Apply a few coats, allowing each layer to dry before adding the next.

However, once you've added your soil you won't be able to access the inside again, so I suggest adding a lining of Builder's plastic to prevent the soil from coming in contact with the timber. Leave the bottom open to allow drainage.

Remember that timber used externally needs to be treated and timber in contact with soil needs a higher treatment again to resist rot, decay and insect attack. Using untreated timber externally is not recommend and means that it will have a limited lifespan, so that should be expected.

Please let me know if you have any questions.

Mitchell
 

[diybaby]

Thanks so much! As I’ve had cancer and trying to be as organic as possible the untreated was recommended to me in store but hearing what you’re saying is to be lined with plastic anyway now. Oh well. Lessons learned the expensive way! Will give it a go and hopefully all goes ok. 

[diybaby]

Hey Michell - I went to bunnings and they gave me Panda mat - what side should I use? I am trying to google and it seems like maybe a goo idea to put the white facing outwards to keep the beds warm? BUT they are in direct NZ sun all day (North facing beds) so then I am thinking should the black be on the wood - confused lol 

ONe side is for keeping the veggie beds cool and the other for keeping the heat in? Is that how it works?

[JacobZ]

Hi @diybaby,

There won't be much difference either way. As most of the Panda Film will be buried and the idea is that the different colours reflect or absorb sun rays in different ways, the only difference will be any that is above the soil line.

Dark colours like black will absorb sunrays, whereas light colours like white will reflect it. With this in mind, I'd suggest the white side should be facing the timber and the black side should face the plants. You don't want to reflect unnecessary sunrays on your veggies.

Let me know if you have any further questions.

Jacob

[diybaby]

excellent - thank you and that with also look better too on the wood gaps. white will be easier on the wood