You can buy tabletop herb gardens complete with a grow light, but their cost (often $100 or more) can be excessive. For example, here's a link to a very nice Tabletop Herb Garden Kit, but it costs over $100. Our goal was to avoid buying expensive fresh herbs from the produce isle, so why would we want to spend $100+ to do that? Our little Herb Garden cost us about $25, but would be even less expensive if you already owned a suitable florescent light that you could re-purpose for the project.
We needed to supplement the amount of natural light provided by our north facing kitchen window. To do this we purchased an inexpensive 18" fluorescent light fixture (fitted with an 18" grow light) and attached it to the bottom of the window blinds. By attaching the light to the blinds we could easily raise and lower the light, as well as set the light at an angle if necessary to maximize the amount of light reaching the herbs.
When choosing your window, be sure to pick a window that is neither too hot or two cold for your herbs. For example, a south facing window in Arizona might get too much light and heat for your herbs scorching them in the hot sun, while a poorly insulated (i.e. single pane) window in North Dakota during a chilly winter might expose your herbs to air that is too cold to allow your herbs to sprout. In other words, your kitchen window may or may not be the best window for this project. You'll want a nice cosy warm (but not hot) environment for your herbs to sprout.
Step 1: Materials Needed
2. Grow Light (bulb) - $8 from Home Depot
3. Windowsill Herb Garden Kit - $10 from Home Depot
4. Velcro strips or Zip Ties to attach the light to your window blinds (not pictured)
5. (Optional) 1/2 quart Starter Herbs (use these if you prefer not to grow your herbs from seed).
Pick a light fixture that is a suitable size for your window. We have a 24" kitchen window, so an 18" light was just the right size.
You'll need to replace the bulb with a proper grow light. A regular fluorescent doesn't provide the complete spectrum of light your herbs will need to grow big and strong. Make sure you find the right size (in both length and diameter) for your fixture. If your fixture takes an 18" T5 bulb, an 18" T13 bulb won't fit. Ask a sales associate for help to make sure you get the right replacement grow light for your fixture.
The windowsill herb kit is optional. You could also purchase 4 or 5 small pots. Just make sure that the pots have a hole in the bottom for proper drainage. You'll also want to purchase a drip tray to protect your windowsill from water damage (the kit comes with a plastic tray already). We found that the kit (which includes seeds) was cheaper than buying 4 pots, a drip tray, and seeds separately. The seed packets themselves range from $1 to $1.50 each.
You'll need a way to attach the light to the window blinds. We used 3 velcro strips. But zip ties would work just as well.
You can also purchase pre-grown starter herbs in 1/2 quart pots. This speeds up the process by several weeks. If you're impatient, this might be the right option for you. Our kit came with Chives, Parsley, Cilantro, and Oregano, but we decided to also purchase 1/2 quart pots of Cilantro and Rosemary. Our kit didn't come with Rosemary, and we wanted to get a head start on the Cilantro, so that's why we went with the 1/2 quart pots for those herbs.
Step 2: Contents of the Kit
You could easily put this kit together by buying individual pots and seed packets, but we priced it out and discovered that it was actually cheaper to buy the kit. However, if you can't find a kit at your local store, here's what you need:
4 pots with drain holes, a small bag of potting soil (or 4 dehydrated soil disks), a drip tray that all 4 pots will fit on (to protect your window sill from water damage), and 4 packets of seeds.
If you want to use the soil disks, you'll need to re-hydrate them. They expand a lot (4x or 5x their original size) so make sure you soak them in a large enough container. A Tupperware container similar to the size of the plastic pots will work just fine. You can't use the pots themselves because they have drain holes in the bottom and the disks need to be soaked in standing water.
We chose to use regular potting soil instead of the soil disks. It just seemed easier.
Step 3: Planting Your Seeds
Once you're seeds are planted and covered, carefully apply water to the soil until it is thoroughly soaked. Just be extremely careful not to disturb the seeds you just planted. Allow the pots to drain in the sink before placing in your herb box (otherwise your drip tray may overflow and damage your windowsill).
Step 4: Arrange Your Pots and Place in the Windowsill
Make sure you orient the fixture correctly so that the power cord can reach a nearby outlet.
Step 5: Adjust the Light Height and Angle to Maximize Light Exposure
If you have all seeds you'll want the light positioned an inch or so above the top of the soil. Once your herbs start to sprout continue to raise the light up so that it is always an inch or so above the tallest leaves. Don't allow the herbs to actually touch the bulb since it may get hot enough to damage them.
If you have a setup like ours where you've got one tall plant at one end and a short plant at the other, feel free to set the light at an angle. It may look a little funny, but it's providing the maximum amount of light to your plants, which is exactly what you want.
That's it! I'll update this project in a few weeks once the seeds sprout. Good luck and have fun!