How to grow your own ginger, papaya, and pineapple — from food scraps

Temple University horticulturist Benjamin Snyder is something of a Dr. Frankenstein. For years, the greenhouse manager of Temple’s Ambler campus has experimented with growing fruits and vegetables from food scraps. Imagine homegrown papaya, harvested from a pot in your south-facing window.

“You can experiment with so much right from what you buy at the store — potatoes, carrot tops, celery, really any produce item that has seeds and is labeled as certified USDA organic,” Snyder said.

He has attempted to cultivate everything from dragonfruit to Chinese water chestnuts, all from scraps. Not every experiment has been, ahem, fruitful, but most have yielded an attractive houseplant at the very least.

“Even if you grow a papaya plant and it doesn’t produce fruit, you’ll still have something beautiful and unusual growing in your living room. And you got it basically for free,” Snyder said, balancing it with the fact that the process is slow-going. It can take more than two years for a pineapple plant to fruit.

Here’s how to grow three of the most approachable scrap-based plants, from easiest to most challenging. Take one look at an adorable baby pineapple, and you may not be able to resist.

Choose a light-colored ginger root, which indicates freshness. Darker ginger has been sitting in storage, which decreases its ability to sprout. Also look for roots with multiple “eye” buds.

Fill a 6-inch-wide plastic pot (4-5 inches deep) with potting soil. Press the ginger root into the soil, until it’s half-submerged. Water until you see seeping from the pot’s drainage holes. Place in an area that gets four to six hours of direct sun, ideally near an east-facing window. Ginger does best between 70 to 75 degrees, but it can weather cooler temperatures (expect slower growth). Fertilize every other week, following package instructions.

Expect to water about twice per week. Sink your finger an inch into the soil; if it’s dry, it’s time to water. Use a watering can, not the sink; too much water can cause the root to rot. If the plant is too dry, the leaves will begin to curl.

The ginger root will sprout green stems from its eyes. Transfer to a larger container when it starts to split open its pot. After about six months, it will grow a new root, at which point you can harvest pieces from it, leaving any green stems intact. (Ginger leaves can be steeped to make tea.) When you break off a piece, a new root will grow in its place; regrowth can take up to six months.

Mexican and Hawaiian papayas are the most popular in supermarkets. If you can choose, opt for Hawaiians (the smaller of the two). The larger the papaya, the more energy it takes to fruit.

Cut the papaya in half lengthwise and remove the seeds, setting aside six on a paper towel. (You ultimately need to grow male and female plants; to maximize your chances of doing so, you’ll want to plant more than two seeds.) One at a time, rub the seeds on the paper towel to remove their gelatinous coating. This prevents mold from growing once the seeds are sown.

Fill a six-cell seedling starter tray with seed starter mix. (Avoid garden soil, which is too heavy.) Place each papaya seed about ¼-inch deep in the soil. Water thoroughly. Place in an area that is ideally warm and not too dry. Sunlight isn’t necessary at this stage. A 75-degree environment is best — the seeds should sprout in about two weeks — but 65 degrees will do.

After the seeds germinate, transfer to 3-inch containers filled with regular potting soil. Place in a spot that gets six to eight hours of sun, ideally a south- or west-facing window. With less sun, the sprout will grow leaves, but won’t fruit. Papaya plants prefer temperatures above 65 degrees and can be placed outside in the summer.

The plants will need to be transplanted as they grow. In about three to four weeks, or when you see roots coming through the containers’ drainage holes, it’s time to move into a larger pot.

Expect to water roughly twice a week. Sink your finger an inch into the soil; if it’s dry, it’s time to water. Give the plants a full soaking.

After eight to 10 months of growth, papaya plants should begin to flower. Identify the males and females: Males produce long, tubular flowers, females produce short, round flowers.

At that time, if your plants are outside, place a female next to a male, and nature will do the work for you. If your plants are inside, take a Q-tip and swab the pollen inside the male flower, then rub it around the female flower. In about two weeks, if the pollination was successful, a fruit will start swelling from the female flower. Depending on the conditions, a papaya will be ready to harvest within six to 10 months.

Choose a pineapple with healthy green leaves.

Twist off the leafy top of the pineapple with your hands; the riper the pineapple, the easier this will be. A small piece of the core should come off with the top — this is where the roots will grow. Trim the leaves from the bottom ½ to 1 inch of the top’s base, then let sit for 24 hours to allow the core to dry.

Fill a 5-inch pot with potting soil. Place the pineapple on top, gently securing the core in the soil. Water until you see seeping at the drainage holes. Place in an area that gets all-day indirect light, ideally a north-facing window or an east-facing window with a sheer curtain. Keep the room between 65 and 75 degrees.

Expect to water about once per week. Sink your finger an inch into the soil; if it’s dry, it’s time to water. Use a watering can, not the sink; too much water can cause the root to rot. If it’s too dry, the leaves will begin to curl.

When you see new green leaves growing from the top, the core has grown roots. At this point, move the plant to a location that gets eight to 12 hours of direct sunlight. The plant will flower in about two years. About four to five months later, the flower will fruit.