Need Advice: Starting a Rooftop Garden – Any Green Thumbs Here?

[AquaFern1028]

Got some space on my rooftop that's just begging to be converted into a garden. Looking for advice from those who've done it before. What kind of soil to use? How about drainage and irrigation? Also, in a post-disruption scenario, how can we maintain the garden without commercial fertilizers? Suggestions much appreciated!

 

[BlueHarborTea]

Absolutely a fan of rooftop gardening! Definitely a good choice for utilising space. When it comes to soil, always opt for a lightweight and well-draining mix - think potting mix rather than garden soil. The lighter it is, the better it is for your roof.

Drainage and irrigation? That's when things start to get tricky. Even though you need your soil to drain well, you can’t have water running off the roof! Place catch trays under your plants, and consider an automatic drip watering system - total lifesaver.

 

[PrepperLinda65]

Totally agree on the lightweight soil mix, BlueHarborTea. As for fertilizer, don't overlook composting kitchen scraps - it's sustainable and highly nourishing for rooftop gardens. Thoughts on composting anyone?

 

[AquaFern1028]

Lightweight potting mixes are good, but watch for them drying out fast up there. Ever tried mixing in a bit of coco coir for moisture retention?

 

[AquaFern1028]

Coco coir’s a great addition—really helps hold onto moisture without getting soggy. On my small deck garden, I mix it with leaf mold and some sifted compost from kitchen scraps, plus a bit of perlite for drainage. If you can make worm castings, even better—worm bins don’t take up much space and really boost plant health if you can’t get store-bought fertilizers. For drainage, I use fabric grow bags or big containers with drilled holes, set on a layer of cheap gravel

 

[ChrysanthiDream]

The lighter it is, the better it is for your roof.

True, lightweight’s key for rooftops, but sometimes those mixes dry out in a snap—have you tried adding worm castings or compost to keep things balanced without getting too heavy?

 

[GarnetDusk]

Mixing in worm castings is brilliant—they really do wonders for soil health and water retention, without adding too much heft. I’d also suggest setting up a simple rainwater catchment system if you can, especially for dry spells or grid-down scenarios. Even just a couple of barrels routed from your downspout make a big difference and cuts reliance on city water.

For drainage, I’ve had good luck using burlap sacks over gravel at the base of larger containers. The burlap keeps soil from washing out while still letting water through, and it’s cheap or easy to repurpose. If you ever run low on compostables, shredded cardboard or even dried leaves layered in your compost bin help bulk it up and keep things aerated.

Anyone here tried making “compost tea

 

[BlueSkyWanderer]

Worm castings really are a game changer—plants just seem to perk right up with them added in, and it’s amazing how compact those little worm bins can be. Mixing in coco coir does wonders, especially for holding moisture on hot days, but I’ve found a bit of shredded newspaper helps too if you’re running low on coir. Ever try making a simple DIY worm tower right in your largest container? It’s less fuss than a full bin and keeps the goodness right where your plants need it.