3 Nitrogen Fixing Plants for the Forest Garden

Michelle | April 25th, 2012

Nitrogen fixing shrubs are valuable in agroforestry systems. They can be integrated into perennial agriculture systems to restore and maintain nutrient cycling and fertility self-reliance. The following 3 nitrogen fixing plants have additional uses and benefits as well. This is a quick snap shot of nitrogen fixing plants. Please share your experiences with these or other plants used primarily to fix nitrogen.

1) Siberian Pea Shrub (Caragana arborescens)
• Ornamental, edible, and can be used in windbreaks
• Does best in full sun
• Tolerant of adverse growing conditions, such as poor, dry soils, extreme cold, salt, and wind
• Can become invasive

2) Ceanothus (Ceanothus americanus)
• Also known as New Jersey Tea
• Non-leguminous nitrogen-fixing shrub native to most of Eastern North America
• Often found in dry woods and gravely banks
• Can grow 2-4 feet tall
• Prefers sandy or loamy soils.
• Does best in well-drained soil but can grow in poor soil.
• Can grow in sun or semi-shade.
• Does not take well to root disturbance or heavy pruning.
• Attracts butterflies, hummingbirds, and birds.
• In addition to fixing nitrogen, Ceanothus has numerous medicinal qualities. It has been used to treat fevers, sore throats, bronchial disorders, lymphatic congestion, and sores.

3) Alder (Alnus spp.)
• Native, non-leguminous nitrogen fixing tree
• There are several species native to Pennsylvania, including A. incarnata, A. serrulata, and A. viridis.
• A. viridis is an endangered species in Pennsylvania.
• Most alders grow 15 to 25 feet tall
• Tolerates a wide range of soils, including heavy clay or poor soils.
• Tolerant of polluted soils and can be used for land reclamation.
• Grows quickly when young, and regrows when coppiced.
• Twigs and branches or coppiced pieces of alder are often used for basketry.
• It is not very durable or very good firewood.
• It does not start to cast shade until late May.
• Has a heavy leaf canopy and can help to build up humus in the soil.

Tips for Growing Lettuces and Salad Mix

Michelle | April 21st, 2012

Growing lettuce and salad mix is fairly simple and can be done in small spaces, including pots. Right now I am growing a mix in a fairly small pot. If only the robins would leave it alone, I suspect I’ll be able to harvest in the next few weeks! I also spent time growing salad mix for a market garden operation.

Lettuces and greens growing on my porch

Keep the following in mind when planning and planting your lettuce bed:

Lettuces and greens are cool weather crops. They tend to bolt (go to seed) much more quickly in high heat and direct sun. Both do well in semi-shade or even mostly shade and certainly prefer spring and fall weather.

The easiest way to manage a variety of lettuces and greens for a salad mix are in swaths of separate varieties in six inch rows separated by enough room for a stirrup hoe (available in three and six inch widths). Weeds are much easier to both see and remove with this layout and harvesting is simpler due to a more consistent size in the lettuces. Another benefit of keeping the two separate is during harvest when a desired balance between the two tastes can be measured.

Maintenance includes weeding, watering, successive sowing, and weekly harvesting. Weeding is a particular concern, as weeds in the final product are undesirable (if for sale) and can sneak their way into a mix. It is also a meticulous process since the lettuces are very fragile and shallow rooted. On the other hand, many weeds are wild edibles and add nutrition, flavor and interest to the mix. Just make sure you know what you are harvesting!

Some wild edibles that are great in a salad mix include chickweed, amaranth, wild chives, and violet leaves.

Lettuce and green seeds can be sown on a rotational schedule to extend the season. This is called successive planting. They generally do best in spring and fall. If you create a cool microclimate (for instance in a food forest), then the summer is fair game too.

5 Steps to Growing Lettuces & Salad Mix

Michelle | April 18th, 2012

Growing lettuce and salad mix is very easy and can be done in the smallest of spaces. It is also a great crop to grow fresh since the shelf life is quite short. It is also a fairly high demand vegetable for restaurants, making it a possible cash crop for small growers and permaculturists. Check out these 5 steps to growing lettuce below:

1) The first thing to do is find seeds! Some factors you may want to consider when purchasing lettuce and green seeds include: cost; organic or heirloom status; color and flavor of greens; local adaptability; and best growing season for different varieties. If your climate tends to be hot or the spot where you will grow the lettuce is direct sun, look for “slow to bolt” varieties for best results.

There are also pre-made mixes available, though these have a few drawbacks. First is that brassicas and lettuces are easiest to manage when they are separated. Brassicas have specific pest problems that lettuces do not have and the germination and growing times of each are different. When cutting for a salad mix, it is best to cut the whole swath and so if you have some short lettuces and some taller, it will be difficult to do.

2) Prepare the soil as for any other seed, with the exception of adding additional organic matter (this is not necessary since the lettuces are harvested when young). It is good practice to make sure there are not rocks or coarse debris on the soil surface.

3) Sow the seeds evenly, pat down and cover with a very thin layer of soil. This should then be “watered in” with a light misting hose or watering can.

To grow lettuces that will be allowed to grow to full size, prepare the soil as above but rather than spreading the seed, sow just a few seeds per hole.

4) Watering twice a day is generally needed, though good practice is to check the soil. When watering, it is best to do it early in the morning or in the evening. Also be cautious about watering the leaves, they are more prone to burning when wet so water low.

5) Harvesting happens when the leaves seem big enough to eat. To have repeat harvests, be sure to harvest above the growth point. Cut and grow lettuces generally can be harvested 3 times before the nutrients and quality begins to go down.

Green Deer Tongue, Strela green, and Black-seeded Simpson varieties of lettuce grown by me for market. Note the space left between varieties for a small stirrup hoe to make for easier weed management.

Be sure to read Tips for Growing Lettuces and Salad Mix!

Pittsburgh Permaculture