How Many Plants Can You Fit Per Acre?

It is easy to forget how big an acre of land is. In planning for planting I often find it useful to think about how many plants I can fit in an acre of land with a given spacing.

Plants per Acre Table

         Number of Plants

Distance Apart

3 in x 3 in 696,960

4 x 4 392,040

6 x 6 174,240

9 x 9 77,440

1 x 1 feet 43,560

2 x 1 21,780

2 x 2 10,890

3 x 1 14,620

3 x 2 7,260

3 x 3 4,840

4 x 4 2,722

5 x 5 1,742

6 x 6 1,210

7 x 7 881

8 x 8 680

9 x 9 537

10 x 10 453

15 x 15 193

20 x 20 108

30 x 30 48

40 x 40 27

Here is an example of how we'd use this chart on the farm. We plan on using half of our land to support the other half by growing compost crops on it. If we were to use comfrey as the only plant for the support section we would need 3 acres of comfrey. If we planted it with 3 x 3 foot spacing we would need to have 14520 comfrey plants on the property. (That's a lot of comfrey!)

If we were planting large trees that needed significant spacing like pecans we might use the 40 x 40 foot spacing which would give us only 27 trees per acre. We won't be, but if we did, we could plant something small like carrots with the 3 in x 3 in spacing and have almost 700,000 carrots per acre!

Does Comfrey Need TLC?

Comfrey is an incredibly robust plant but giving it some love just makes it produce even more. Here are comfrey plants that were all planted at the same time (6 months ago) and are only a few feet away from each other. They were all started from Bocking 14 root cuttings.

This root was planted in poor soil (hard, crusty clay) and not given any attention. After 6 months all it has produced is 2 little leaves. If I had given it any attention - extra moisture/nitrogen/mulching it probably would be thriving just like my other plants.
Just a few feet away is another plant that is in better soil but still didn't receive any extra attention. Several leaves and growing well but nothing amazing.
And finally these plants were planted in a low lying area that receives significant moisture and nutrient run off. They are only 6 months old but easily look like plants that are a couple of years old.
So to answer the question - does comfrey need TLC? Yes and no. If you just want some comfrey to grow and don't need leaves immediately, then putting it anywhere will do. However, if you want to see all that comfrey can do then you'll need to put it somewhere nice. A perfect place can be downhill from a compost pile. It will receive nutrients that runoff the pile and will put on significant growth in no time.

Comfrey as Mulch

Using comfrey as a mulch in your garden/farm is a great idea depending on your needs.  If you are looking for a mulch that can start feeding your crops really quickly, this is your answer. The leaves of the plant are low in fiber so it breaks down quickly after mulching with it. Depending on several factors, it can easily decompose within days providing nutrients to the soil underneath it.

For mulching with comfrey there are 3 options all of which have big benefits.

Move to location – This simply involves cutting the leaves off a comfrey plant (or harvesting the entire plant) and using them as mulch elsewhere. This is what we do for our raised beds on the farm. We have a comfrey patch that is near the beds, and when needed, we cut off leaves and bring them up to the bed. A small patch can be used to mulch a rather large raised bed.

 This is one of our <1-year-old comfrey patches used for that purpose - 
Once established this patch can produce a ton (yes, 2000 pounds!) of comfrey leaves a year. 

Chop and Drop – If you've planted your comfrey plants near (within the drip zone) the trees you want to fertilize you can simply cut off the comfrey leaves where they are and leave them. Almost as easy as possible.

Let die in winter – As easy as possible. Again for comfrey that has been planted near trees you can simply let the comfrey die back each winter fertilizing the ground around the plant. You don't get as much mulch as you would if you cut it back a couple of times during the year, but it requires absolutely no work. Some call it lazy, I call it being efficient. 
Here is comfrey as it begins to die back during winter. The dead leaves are very dark in color which makes the soil darker as it enriches it. - 

We Love Comfrey!

Comfrey is our favorite and most important plant on the farm.

We grow more comfrey than any other plant number wise and space wise. We currently have about 1000 plants and hope to eventually have over 5000.
Books have been written about this amazing herb over the years so I obviously won't be including all of that information here. I do want to highlight some of comfrey's most positive features so that everyone can understand how great of a plant this is.

Sweet Potatoes

Our first harvest of sweet potatoes are coming in.

This is the harvest from just one plant. Those sweet potatoes weighed in at 7 pounds give or take a few ounces. A very brief search online indicated that the average harvest is about 2.5 pounds of sweet potatoes per plant so we are doing very well so far.

My wife makes sweet potato burritos fairly often and then freezes them to have a quick and healthy dinner when needed. Our goal is to grow 200 pounds of sweet potatoes next year and make them one of our staples. We'll see how that goes.

Growing sweet potatoes well is an interesting challenge because they do NOT perform well in soil that has high amount of nitrogen which is the opposite of most other plants we grow on the farm.

2013 Spring Planting List

Spring 2013 Planting L6ist

Raised beds- 

Good King Henry
Oregano, Greek
Sage, Culinary
Tarragon, Mexican
Winter Savory
Perpetual Spinach Chard
Sorrel, French
Garlic Chive

Admiral Peas
Sugar Snap Peas
Georgia Collards
Spinach, Matador
Chard, Ruby Red
Onions, Valencia
Carrot Mix

Quinoa, Colorado
Corn, Anasazi
Corn, Festivity
Scarlet Runner Bean
Celery, Golden Self Blanching
Jalapeno Peppers, Early
Pumpkin, Kakai
Marigold, French
Sunflower, Mammoth
Bush Blue Lake Bean
Spinach, Egyptian

Forest Garden
Gumplant, Grindelia
English Lavender
Stinging Nettle
Balloon Flower
Amole, Soap Plant
Misc plantings -

Linden Tree
Siberian Pea Shrub