- Growing containers
- Potting soil
Fruiting vegetables, such as eggplant, tomato, cucumber and squash, need more space than the average home or school can offer. To get started on greens, however, you just need a few things: A bright sunny window and/or grow lights, seeds, pots and soil. Growing greens indoors not only provides you delicious salad ingredients, it can be a conversation starter about where food comes from. Compare the taste of store bought greens to home grown greens. Discuss the advantages and disadvantages of buying shipping food across the country and eating locally harvested foods.
- At a local garden center select quick-maturing varieties of greens that won’t grow too large, such as ‘Tom Thumb’ or 'Black Seeded Simpson' lettuce varieties or other greens like arugula. Also purchase soilless potting mix and plastic growing containers. Rather than buying pots, you can also be creative and grow salad greens in recycled household containers. For example, the clear plastic containers that store-bought lettuce mixes come in make excellent growing trays. The key with any homemade container is to poke drainage holes in the bottom and be sure to put a drainage dish below.
- Locate a window in your indoor space that provides the most sunlight available to you. Generally windows facing the south receive the most sunlight followed by those facing west. Optimally, choose a location with 8 more hours of sunlight available (indoor light will not be as intense as outdoor light thus making it important to receive a longer duration). The amount of sunlight will not only be determined by direction, but also by shade from roof overhangs, trees or surrounding buildings.
- During winter months, the sun is at its lowest angle in the sky and its lowest intensity of the year. The days are too short and dim for good plant growth. However, using a simple shop light or a grow light system, you can increase the light intensity indoors enough to grow greens even during the darkest months. Purchase a 2- or 4-bulb fixture and use either full-spectrum grow lights (the best option) or a combination of cool-white and warm-white fluorescent tubes. These bulbs will give your greens seedlings the right combination of light wavelengths and intensity to grow strong and full.
- Have your child or students fill your containers with moistened potting soil. Moisten the soil in a bucket or bowl before placing it in your container. You want the soil to feel like a moist sponge, but you do not want it to be so wet that water can be squeezed out of it. You may need to alternate adding water and soil until the optimum moisture is achieved.
- Next, sprinkle the seeds about 1-inch apart on the soil surface and barely cover them with soil. Because the seeds of greens are so small, you may want to help young children with this step.
- Place the planted containers in your window or under lights and keep the seeds and soil moist. If using lights, keep the bulbs on for 14 hours a day. Once the seeds germinate, keep the lights positioned just a few inches above the seedlings. Adjust the lights daily as the plants grow. A timer is a worthy investment, so you don’t have to remember to turn the lights on and off. If your plants are placed in a windowsill, make sure to rotate the pots every couple of days since once side of the plants will be getting more light exposure.
- Water as needed. If the leaves turn pale green or yellow, give the plants some liquid fertilizer when watering, being sure to follow the manufacturer's instructions.
- Once the leaves on the greens are a few inches tall, it’s time to start harvesting. Remind your gardeners that you won’t be growing full heads of lettuce like the ones you buy at the store. The idea is to harvest a few leaves at a time from each plant and then let them grow again. That way, the plants won’t take up too much space and you’ll get multiple harvests. Harvesting is easy. Using scissors simply cut the greens 1 inch above the soil line, leaving a few larger leaves in the center to keep plants healthy. Lettuce, spinach and mesclun greens will grow back to yield another harvest in a couple of weeks. After a few harvests the plant stems may get thick and the leaves may remain small. This indicates it’s time to compost the potting mix and roots, and start over.
- Depending on the size and number of containers planted, your harvest may continue for many weeks. For fun, purchase a package of store-bought greens and do a blind taste test against your homegrown greens. See if your young gardeners can tell the two apart.