I just put together a 10x4 raised bed garden using cedar boards stacked 2 high.

I am a little concerned that the small gap between the stacked boards will let water seep out.

Could you provide any recommendations for sealing this gap? It would have to be soil/food safe.

My initial thought was to use 100% silicone caulk along the inside of the gap. Do you think this is a good choice or are there better options?

  • 1
    If there is so much water and so little drainage that there is water that wants to seep out, you have a bigger gardening problem than "how to seal up the leak" - you have a pond full of mud, not a raised bed!
    – alephzero
    Jan 31 '19 at 16:43
  • I suppose your right. First time doing this. I didn't want soil to slowly erode out of the sides either. I live in a very hot area, so I wanted to retain the moisture as well. I don't have soil in this yet, so I don't have a problem yet.
    – zeal
    Jan 31 '19 at 18:13
  • Is this raised bed built up on top of soil, or on a hard surface? Is it open at the bottom, or is that boarded too?
    – Bamboo
    Jan 31 '19 at 18:16
  • 2
    Landscape fabric or geotextile
    – kevinskio
    Feb 1 '19 at 0:10
  • The bottom is open on clay/dirt. I was going to cover the dirt with landscaping fabric. Putting the fabric along the wood makes sense.
    – zeal
    Feb 1 '19 at 1:23

It was completely unnecessary to seal the cracks in the raised bed. I did however line the inside of the wood with landscape fabric.

Update: After a year, I recommend NOT sealing the gaps between boards in a raised bed garden. You actually want water to leak from these during heavy rains so that it does not flood your raised beds.


Depending on the drainage of the soil content that your bed is laying on and if it's open on the bottom there's a lot of scenarios to take into consideration if you're sitting on a Sandy based area and your bed is open on the bottom the water is going to perk straight through with no issues. sand actually allows water to go through it quite quickly clay on the other hand is a compacted material which will hold water again all factors to take into consideration when and thinking about sealing the joints of your bed

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