Five years ago, Nicole Enders and her husband bought their first home on a quiet, tree-less block in South Philly. While their street lacked greenery, just behind their kitchen lay an enclave brimming with plant potential — a 170-square-foot back “yard.” Enders considered it one of the rowhouse’s biggest selling points.

“It was just a cement patio with cinder block walls. But I immediately envisioned vining plants growing up those walls,” says Enders. “Now they’re filled with cucumbers every summer.”

In the spring, before the cucumber vines begin to fruit, Enders’ patio flourishes with buttery lettuces, hearty Red Russian kale, bushy sugar snap peas, fragrant rosemary, and other herbs and produce, mostly rooted in raised beds. About a quarter of her patio is devoted to gardening. It’s a small but lush escape away from summers in the city, says Enders, who today helps others transform their rowhouse yards into gardens, too.

The owner of Philadelphia Box Gardens, Enders specializes in planning and installing edible gardens in small urban spaces. And she’s shared a guide for starting your own, including how to build a raised bed, grow within it, and make your rowhouse garden thrive. The material costs generally clock in under $150 for a bed that’ll last for years to come.

Note: Constructing the bed will be easier if you have some experience working with tools, but the design is relatively simple. “It’s not quite a beginner project, but if you have a helping hand, two people with little experience I’m sure could put this together,” she notes. “The most challenging part is making sure it’s square at the end. And that’s really just for aesthetics.”

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Why a raised bed?

Many urban gardeners start with small pots or planters. While it’s a simpler set-up, it’s often a harder path to take if you want an actual harvest, says Enders.

“Small pots need to be watered more frequently, and certain plants need more soil for root development and nutrients than a small pot can provide,” says Enders. “The raised bed is much more forgiving to a beginner — in terms of watering, drainage, and just general upkeep.”

In other words, it ups your chance of successfully yielding beautiful heirloom tomatoes and carrots worth digging for.

Even if grass, rather than concrete, fills your Philly yard, Enders still votes for a raised bed, unless you get your soil tested. (Located in the Navy Yard, Penn State Extension offers $9 soil testing kits.) Your soil may have contaminants that can harm both your plants and your health. “By building a raised bed, you also have control over the soil content so that you can create better and more even water retention,” says Enders.

If building directly on top of grass, stretch a layer of landscape fabric across the bed to hold your fresh soil in place.

How to build a 4-foot-by-4-foot raised bed

All materials can be sourced at Lowes, Home Depot, and most local hardware stores. Double check that all the boards are the same length before heading home.

Once built, consider location. If space allows, position your bed in the part of your yard that receives the most daily hours of sun. (Observe how trees or buildings might impact this throughout the day.)

MATERIALS:

  • 4 (2-inch by 6-inch by 8-feet) Cedar* or Douglas fir dimensional boards, cut in half, so you have 8 (2-inch by 6-inch by 4-feet) pieces (most hardware stores can do this for you)

  • 4 (10-inch) framing angles (found in the “decking” department of most hardware stores)

  • 24 (¼-inch by 2.5-inch) hex screws

  • 24 (¼-inch) washers

  • 24 (¼-inch) nuts

  • 16 cubic feet of soil (see below for instructions)

* Cedar is rot- and insect-resistant but more expensive

TOOLS:

  • Drill

  • ¼-inch drill bit

  • Pencil

  • Tape measure

  • Framing square

  • Wrench

  • Bolt tightener

ASSEMBLY:

Step 1: Make front and back panels

Grab a board, and use your tape measure to measure its thickness. (Lumber is generally thinner than advertised, so your boards are likely to be around 1.75-inches instead of 2-inches thick.) Jot the exact measurement down.

Arrange four boards in front of you horizontally. Grab your pencil. Use the measurement you just took to draw a vertical line on both ends of each board, measuring left to right and right to left.

With the boards still horizontally in front of you, lay a framing angle across the left side of the bottom two boards, lining it up along the inner edge of the vertical lines you drew. The framing angle will lay vertically across the two boards and make an L-shape.

Use your pencil to mark three holes along the framing angle, with one hole per board. This is where you’ll drill to secure the framing angle to the boards. (One board will have two holes, and one board will have one. It doesn’t matter which holes you mark, as long as the marking isn’t in the crevice between the two boards.)

Drill an initial set of pilot holes. Then secure the framing angle to the interior of the two boards, using the hex screws on outside of the boards, and washer/nuts on the inside. Repeat to secure a framing angle on the right end of the boards. (This time the framing angle will make a flipped L-shape.) Repeat with the second set of boards.

You should now have two panels with framing angles on both ends.

Step 2: Make the side panels (A partner is helpful here.)

Grab your remaining four boards. Stand up two boards so that they’re in a vertical position, and place them along the edge of one of the panels you just created so that their interior is flush with the framing angle. Your boards should make a large L-shape. Ensure edges are straight.

Using the framing angle, take your pencil and mark three holes for drilling. Be sure to have one hole in each board. One board will have two holes, and one board will have one.

Lay the vertical boards back down, and drill pilot holes in the spots you just marked. Return the boards to a vertical position, and attach them to the framing angle, using the hex screws on outside of the boards, and washer/nuts on the inside. Your first corner is complete.

Repeat this process with two boards on the opposite side so that you create a U-shape.

Lay your U-shape onto the ground, and make sure all angles are flush and at 90 degrees. Now slide in the remaining two boards to complete the square.

Using the framing angle, take your pencil and mark three holes for drilling. Remove the boards, and drill pilot holes in the spots you just marked. Slide the boards back in place and attach, using the hex screws on outside of the boards, and washer/nuts on the inside.

Once the bed is complete, make sure everything is aligned. Then use a bolt tightener to tighten all the bolts.

Step 3: Fill your raised bed

Evenly scatter your bed with 16 cubic feet of soil. You want to create a mix of soil that is:

  • 25% mushroom (or other bagged) compost

  • 25% top soil

  • 50% raised bed or vegetable garden potting mix

You can buy bags of each. Bags are usually sold with one or two cubic feet of soil per bag. At the end, your bed should be filled with approximately one-foot-deep of soil.

What can you grow in a 4-x-4 bed?

How much to plant

A small bed can fit a surprising amount of produce. “In an urban space, you don’t have the luxury of farming in rows like they instruct you on most seed packets, so I like to break the rules and instead follow an intensive planting strategy,” says Enders. “This means I’m packing plants closer together and harvesting regularly, opening up space throughout the week for plants to continue growing.”

Enders recommends allowing at least a foot of space between larger plants, like tomatoes, a quarter-foot between medium-size plants, like Swiss chard, and two to three inches between smaller plants, like radishes. If you pack your garden tighter, you may see stunted plant growth, less fruit, and more pests and disease. “Experimenting with boundaries is good. If you start to see any of that, just pull the plants that are struggling and make more space,” says Enders.

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What to plant

What you plant will depend on how many hours of sun your bed receives, often dictated by which way your yard faces. South-facing yards generally receive the most sun, followed by east- and west- facing yards, and then north-facing yards. But in the city, this can also depend on the buildings around you.

With more sun, you can grow fruiting plants, like tomatoes and eggplant. Shadier plots do better with leafy greens, and many root veggies, like carrots and radishes. Enders also recommends Calendula, an edible flower also known as Pot Marigold.

“It’s a pollinator, so it brings bees and butterflies to your garden, which is less important if you’re not planting fruiting crops, but visually it breaks up all the green, and you can toss the flowers on salads,” says Enders.

The diagram below represents a sample plan for how you can map out your garden. Each circle marks one plant and is scaled to give an idea of how much space it needs.

When to plant

As soon as the ground thaws and you’re able to work the soil, you can start planting. Crops like lettuce, broccoli, kale, and carrots can all go into the ground in mid- to late- March.

“Transitioning into summer is sort of a ‘what brings you joy’ moment, where you’re prioritizing your garden,” says Enders. “Once temperatures rise above 65, you can start planting summer crops, which means you can usually put tomato plants in by the end of April. But if you want to hold onto your spring crops because you love them so much, you can wait.”

Exact timing depends on the crop. To guide your planning, check the Farmer’s Almanac, which provides planting dates tailored to Philly’s frost dates.

You can start plants by seed indoors, but if you’re new to gardening, some plants are easier to cultivate by starting with seedlings or starter plants. These include tomatoes, peppers, eggplant, brassicas (like broccoli, cauliflower, and cabbage), and herbs (like thyme, parsley, and oregano). Plants that prefer to be directly sowed into the soil by seed include peas, beans, zucchini, cucumber, melon, carrots, and radishes. Greens, including kale, Swiss chard, lettuces, kale, and Asian greens, like Tatsoi, transplant well but are also easy to grow from seed.

Raised bed gardening tips

Save money by planting by seed. “Seed packets run roughly $2 to $4 per pack for 25 to 500-plus seeds, whereas starters are roughly $3 to $4 per plant,” says Enders. “Some of the easiest plants to grow from seed are lettuces, greens, beans, peas, roots, squash, and melon.”

Utilize height to make more growing space. “Adding a trellis can increase your production abilities greatly in a small space, and you can get creative with patio walls too,” says Enders. Veggies that love to grow upwards include peas, pole beans, cucumbers, tomatoes, and squash.

Water deeply and regularly. Create a routine schedule, adapting it to the weather (heat waves, storms, etc.) and also your environment. A south-facing bed may need more water than a tree-shaded, east-facing garden. But generally, aim to water every two to three days. “If you have a one-foot-deep bed, you’re watering just until you see water seep out, or until the soil is wet all the way down when you stick your finger through,” says Enders.

Water the soil, not the plants. “The roots are what’s drinking up the water, and wet leaves can lead to disease,” says Enders. “Of course your leaves get wet when it rains, but even then, you want to avoid touching the leaves and then touching other plants because you can transfer disease.”

You can keep your soil from year to year. Just add compost. At the start of the growing season, add two to three inches to the top to restore nutrients and volume.

Go organic. “Don’t be discouraged by having to pull a disease or pest ridden plant,” says Enders, noting it’s a better solution than pesticides when working in a small space.

Feed your plants. “Compost is the easiest way to maintain a lush garden,” says Enders. “I add a handful of compost at the different growing stages, so I’ll add when the plants are first planted, once they’ve doubled in size and they’re working on foliage growth, and then in the flowering and the fruiting stage.” Become a member of local composting program Bennett Compost, and you’ll get two five-gallon bags for free.

Squirrels and birds bothering your garden? “Birds will mostly go after young seedlings in the spring, and their damage becomes less apparent as the season goes on,” says Enders. “Squirrels want to dig in the soil to retrieve anything they hid there through the winter, and they want to steal your ripening fruit.” Bird netting can help deter both. You can also tie mesh bags around tomatoes to try to protect them. “Or you can plant with an abundant mindset and plan to share,” says Enders.

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