Friends of mine have a small Christmas tree farm in Martinsville, Indiana. We're working on starting a market garden and looking at other possibilities as well. They have gardens areas established but I'd like to be able to plant in and amongst the Christmas trees to get more production from the area and hopefully reduce or eliminate mowing. Any ideas?
"Sitting at our back doorsteps, all we need to live a good life lies about us. Sun, wind, people, buildings, stones, sea, birds and plants surround us." - Bill Mollison
What is the pH of the soil around the Christmas trees? Conifers can have an acidifying effect, but it could be good to do a few pH tests and get an idea where it is at.
How densely are the trees planted? I'm asking this mostly from a shade perspective. I'm not very familiar with Christmas tree operations, but the native spruce stands around here tend to be very shady.
How wet is the soil? If the soil is acidic (I'm just making an assumption, it might not be) and wet then there are a lot of plants adapted to growing in peat bogs.
How tall of plants are you willing/able to have? Do they need to be something that can be driven over?
Are you mainly looking for edible production or are flowers and medicinals of interest to you as well?
Members of the Ericaceae family of plants tend to like acidic conditions. These include the genus Vaccinium (blueberries, cranberries, lingonberries, huckleberries, and many other edible berries) and several ornamentals like rhododendrons and azaleas. Many of these grow low to the ground, which would make access to the trees easy. A lot of the lower growing ones like full sun, which might be a challenge. Huckelberries around here do well in dense shade, but they can get to be fairly tall.
If I remember correctly rhubarb and serviceberry do well in acidic soil. Rhubarb stays nice and low, while serviceberries can be anything from bushes to small trees. Rhubarb likes sun. I don't have much personal experience with serviceberries, but from what I've read they can tolerate heavy shade but production drops off substantially.
Going with another conifer, there are varieties of juniper that are prostrate and used as groundcovers. Blue carpet is popular here.
Edited to add that a lot of what I've read in regards to shade is from a far north context. It seems like a plant's preference for shade or sun often has to do with how hot the summers are. Your mileage may vary.
You could grow potatoes in straw beds between the rows of trees, they do well in acidic soil provided they get enough sun and would give you marketable veggies. Broccoli, cauliflower, squash, tomatoes and pumpkins grow well in acidic soil as well. You have the added benefit of having organic matter quite close by if you need it, though I doubt you do. That being the case fertilize with lots of manure for the nitrogen and I think you would do quite well. These are veggie varieties that we grow and here the PH level is around 5.8...really acidic; and these do well. With a lot of lime you could get the PH level up and take on any kind of veggie though. It just would take a year or two.
A soil sample would tell you where you are and where you need to be. It is always best to start with veggies that fit your soil and then move to improving it after you get going so your start up costs are not so high.
You could look into blueberries between the trees. They love acidic soils and could potentially provide additional income once they're producing well. There's other posts on here about planting blueberry guilds that have tons of information. Other than that, I'm working on gathering options for conifer friends as well but mine are quite a bit taller than Christmas trees
Collection of 14 Permaculture/Homesteading Cheat-Sheets, Worksheets, and Guides