First post on the forum, please let me know how I can improve it before downvoting :)

I would like to build a rectangular planter, (W: 40cm (15in), L: 1m (39in), D: 20cm (7.5in)), in which I would grow grass. It will be kept in interior most of the time.

I am concerned that over time, the wood might become mouldy, and I am not sure how to design the bottom of the box (should it have holes to let water/air through?).

Would you have any advice as to which wood to choose, whether I should apply wax, and whether there is a best way of designing the bottom of the box (eg with holes, or put gravel at the bottom and soil on top)?

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    Welcome Sh3ljohn! This is an excellent first question, no risk of downvotes at all! In fact, just the opposite! I made a few small edits just to make it a bit easier to read, and because we don't usually use bold letters. I added measurement conversions for the few of us that don't use the metric system, but you don't have to worry about that. I hope your planter comes together nicely. We'd love to see more of you in the future! Nov 22, 2016 at 23:52
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    @Sue What a lovely comment :) Thank you for improving my post, it is much clearer with your edits!
    – Jonathan H
    Nov 23, 2016 at 9:56

2 Answers 2


There should be drainage holes in the bottom - that necessarily means, indoors, you will need to construct a tray beneath to catch water rather than letting it run all over the floor. There are woods which are good to make planters with, cedar and teak being the most obvious choice because they contain oils which will help to prevent rot without being treated in any other way, but more information on what woods to use here http://homeguides.sfgate.com/type-wood-needed-build-planter-box-52380.html.

You've not said what type of grass you want to grow, but be aware that many ornamental and lawn grasses do not do well without any sunlight, and many may not appreciate being indoors most of the time. If you were thinking ornamental grass, then sedges such as Carex varieties like C. 'Evergold' might do better.

  • I am glad you brought up the tray gig beneath!!
    – stormy
    Nov 22, 2016 at 20:59

Do you have artificial lighting? I love the idea of grasses in a pot indoors. I use ornamental grasses an awful lot...what kind of grasses would you be using? Not so much indoors because lighting is a constraint.

As far as a wood planter, any wood except for pressure treated (will DISSOLVE your screws, seriously I had no idea, you'd have to use powder coated hinges, screws). A really cool product would be Treks or similar. Dimensional lumber made from plastic bottles...looks like wood, cuts like wood, have to drill holes for the screws, can be curved with a little heat and will last forever. No need to line the interior. Comes in dove gray and that really looks like wood. Other colors as well but for planters keep the pot simple and understated so as to to compete for attention.

I wouldn't use Walnut either...

For use indoors all you need to do is LINE your planter with black construction 3 mil trash bag material. Make holes in the bottom of course. 1 to 1 1/2" in diameter and cut the plastic to secure to the rim of your holes. There should be no blockage with wrinkles to catch water. No rock or gravel at the bottom below the soil. Only use sterilized potting soil. Shallow is better than deep! Most roots of most plants are within the top 4-6" of soil. The excess is fine for plants that will send roots down deeper but grass is pretty shallow and I don't think you will be able to make a long term planting of grasses. The best grass would be fescue. fine fescue lawns It is shade tolerant and very fine. Another suggestion would be blue fescue, Elija Blue. Tidy clumps of blue blue grass. Very structural/architectural versus the green fine fescue. The third suggestion would be Hamelin Fountain Grass; 2-3' high.

The soil will not come out again past the first few waterings but covering the hole with panty hose before filling with potting soil would be a good idea for indoors.

Use linseed oil after sanding very finely.

You should consider grow lights to be able to have vigorous more of a long term perishable. Great fertilizer and for this I would definitely use an organic slow release fertilizer. Better for plants in limited light and comes with necessary bacteria and fungus plants need for health. Not too much because of the light factor. Specialized pruning, mowing for different grasses. For instance the 'evergreen' grasses such asevergreen ornamental grass don't do well with cutting back. Just saying get to know the grass you are considering and expect to change it out for another grass from time to time. Plant the old grass out in the garden in pockets of a 'rock' garden or give away.

  • This is full of good advice! I didn't know about Trex lumbers, that seems to be an excellent idea, although there are only deck boards available in the UK and they are quite wide (14 cm), but I guess that would be high enough (28 cm would be too deep). Fine fescue lawn looks great, would you have any other recommendation for fine and soft green lawn by any chance?
    – Jonathan H
    Nov 23, 2016 at 12:09
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    'Deck boards'? So a limited length of this Trex or Treks...there are other companies that make the same stuff. On a fine and soft lawn..why wouldn't the red creeping fescue work?
    – stormy
    Nov 24, 2016 at 3:47
  • That's perfect :) Thank you so much for your help!
    – Jonathan H
    Nov 24, 2016 at 7:00

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