How to Make High-Yield Planters That Practically Water Themselves

As the days get steamier this summer the gardeners out there remember how hard it is come July to keep your basil and hyssop from wilting and your tomato vines pert and perky. Frieda Lim is one local Gowanus gardener who has figured it out, using a “closed system” planting technique called Sub-Irrigated Planters, or SIPs, to create the tiny rooftop farm she calls Slippery Slope.  We profiled Lim and her 75 rooftop SIPs–they’re mainly 18-gallon plastic storage totes typically bought at Lowe’s or Home Depots and used for garage storage, as shown above–on our NY1 segment last week.

A SIP is essentially a planter that has been converted so that the bottom is a water reservoir under a lightweight potting mix. You fill up the reservoir rather than watering the soil and the water trickles up instead of down. With a SIP, you lose less water to evaporation and your plants stay happier and grow healthy with less attention. It’s a concept that’s been used in fields in Europe for years, says Lim, who learned the technique from Bob Hyland, a Brooklyn urban farmer extraordinaire who makes it his mission to get others to grow their own food. ( ran an excellent feature on Hyland and Lim last year.)

SIPs are also nice for New Yorkers, Lim adds, because if you cover the tops with mulch, weeding is almost nonexistent, and because you can avoid lead and other contaminants in your backyard soil, and because you can move ‘em around when you finally score that West Village penthouse with a terrace view of the Hudson.

You can buy SIPs–look for a product called the Earth Box–but they can be made out of any existing windowbox or planter or container, and Lim sometimes teaches workshops on how to do it using plastic water bottles, gutter liners and other cast-off materials. It’s so easy, she says, she’s even taught the grade-schoolers at Brooklyn’s PS 39 to create a SIP-based garden at their school, which Edible Manhattan profiled in a video segment earlier this year.

If you want to learn more about SIPs and urban gardening, check out Lim’s site for more details, as well as Inside Urban Green, the excellent urban farming and food-raising site run by Bob Hyland. And don’t forget to take a peek at what’s being produced at Slippery Slope Farm on

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