Rick Shory

Offering a little something you might not otherwise have

strawberries staying clean on top of bricks

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Garden idea: grow strawberries between bricks

A strawberry patch is great, but a couple problems crop up:

  • Strawberry plants don’t stay in tidy rows. They multiply by runners, till soon you have a tangle. This makes it hard to walk without stepping on the plants — and the berries.
  • The berries tend to rest on the ground where they are prone to dirt, rot, and slugs.
  • Weeds come in between the strawberry plants. They crowd the strawberries and compete for moisture. If the weeds grow tall, they shade the strawberry plants, and cut their production.

Growing strawberry plants in the cracks between bricks solves these problems, and more.

diagram of strawberry plants between bricks

The basic diagram

One key idea of growing strawberries, which I did not know at first, is this: Strawberry plants get old. Say a new plant gets started from a runner. The following year, that plant will bear the most flowers and fruit it will ever have. After that, it will decline. So, for sustainable strawberries, you need to have new plants coming each year, replacing the old.

There are various ways to do this:

  • You can do like commercial strawberry growers: Plow up the whole field each year, nix all the old plants, and re-plant with newly bought starts.
  • Do like they did on my grandma’s farm: Move the strawberry bed every couple years. The family had a general notion a strawberry patch would “run out” after a few years. This was simply the site getting too thick with weeds and unproductive old plants, leaving little space for the new. The answer was to just dig up some of the plants and put them in new ground. This works well if you have a family farm, and kids for the chores.
  • Do like we did at my mom’s yard in Alabama.  There was lawn to mow, and we would dump piles of grass clippings on the strawberry patch. This would smother and kill the plants direct hit. But, in that heat, the grass piles would soon molder into the ground. New runners would colonize the bare spots, so there were always young productive plants. This works well in a hot climate, where you have extensive lawn to mow.
  • Roto-till your intended strawberry plot, and set a stripe of plants along one edge. Next year, roto-till those; but by now they will have spawned a population of progeny a few feet out beside them, from runners. This year, those will be your productive plants. Keep “chasing” the strawberries back and forth across the ground. This works well where you have fine soil you can easily roto-till — and of course a roto-tilller.
  • Grow strawberries in a strawberry jar. Each year, clear out the plants from half the holes. Then train a runner from one of the remaining plants so it starts a new individual in the vacated hole.

With all these in mind, I came up with the brick method. I’d had an old chimney removed, for earthquake safety, It was no longer serving any purpose now that I had a new high-efficiency furnace. So, I had lots of bricks.

overview of brickwork and plants

Overview of the brickwork pattern, with strawberry plants

I laid the bricks out on the ground with finger-width spaces between. I just put them in rows,, but I could have done herringbone, or anything. I planted a few strawberry plants in between.

This was a part of the garden that used to be muddy all winter. To go through there, I needed boards, for catwalks. Even these would gradually squish into the ground. Now, the brickwork provided an easy walking surface. No more mud.

strawberries staying clean on top of bricks

Most strawberries rest on top of the bricks, and stay clean

In due season, the strawberry plants had berries. It was easy to step around among them, on the bricks. The fruit, for the most part, rested on the bricks, keeping up out of the dirt.

This same winter-muddy area would get very dry in summer. Now, the bricks acted like rock mulch, and held in more of the soil moisture.

In their usual way, the strawberry plants sent out runners. These would tend to nestle into the spaces between the bricks, and start new plants there. Sometimes I would help them a bit, nudge them where I wanted them to go. But for the most part, the strawberries took care of themselves.

There were not many weeds because, well, 90% or more of the surface was brick. About the only thing that will grow on bricks is moss.

This has been going on about eight years now. The old plants seem to die off naturally on their own. When a strawberry plants lives into its third, fourth year and beyond, it lays over on the ground and forms a short, creeping stem that roots from the new part, while the old part gets ratty. This can happen on flat ground. However, in my brick bed, the old plants try to “climb out” of their crack, and lose contact with the soil. Then, they naturally dry up, and make room for the new ones.

My brick bed is June-bearing strawberries. These produce a single crop, in spring and early summer. Then, no more berries till next year. This means I seldom have to water the bed. The winter and spring moisture, from the rain, brings in the crop. Then, the area dries out, too dry to get good berries, but the plants are not trying to make berries anyway, so it does not matter. It’s still not as dry as it used to get, before the bricks. The plants tough it out on the residual moisture until the rains come back in the fall.

A brick bed like this would have a lot of the same advantages for ever-bearing strawberries, but you would need to water them through the summer to keep on getting berries. Too dry would mean small, deformed berries, or none at all.


milkweed flowers closeup

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Germinating milkweed seeds

Is there any other flower people plant in their garden hoping the bugs will eat it? To encourage monarch butterflies, many people want to grow the caterpillar host plant, milkweed.

milkweed flower heads

milkweed stalks

I never thought there was anything to it. When I lived in Colorado, a milkweed seed floated into my garden one day, germinated, and set about its usual program of taking over the world.

milkweed spreading through a garden

Yet, here in Portland, many people have told me of failure. “I got the seeds, but they never grew!” So, when some milkweed seeds came into my hands last fall, I decided to see what I could figure out.

ripe milkweed pod, just opening

I was on a garden tour of a native plant nursery. There was a just-ripened pod of showy milkweed (Asclepias speciosa) on the drying stalk. The owner said I could have it. People on the tour were asking how to germinate the seed, and others were clambering “Cold stratify! Cold stratify!”

Now, I have been “cold stratify”-ing seeds since I was a teenager, and think nothing of it. But I have come to realize that for a lot of people, it’s beyond their ken. “Cold stratify” is technically redundant. Stratify means cold, as see this blog.

I had my doubts about milkweed. It’s typically a summer-ripened seed. A lot of summer annuals have a simple germination requirement of dry storage. If the seeds sprouted as soon as they got ripe they wouldn’t have much growing season left, plus, lots of competition from adult plants. So, the seeds have an internal inhibition of germination when they are fresh, which fades over time.

Even though milkweed is perennial rather than annual, I wondered if it might be the same. It sure would be easier if people could forget about stratification! So, this was my hypothesis. That milkweed seeds just needed a period of dry storage to grow. To test it, I would do a series of germination assays, over a period of months, and see what changed.

Cut to the chase. I was wrong. The seeds germinated right away. There was some variation over the months, but probably random. I just put the seeds at about 85°F, and voilà! Milkweed seedlings.

The 85°F temperature was my standard growth chamber, where I was already growing other things. Maybe it was luck.

A good germination test, to be statistically valid, ought to use 100 seeds. My milkweed pod only held about 150 seeds total. So I compromised, and did smaller tests of ten seeds each month (I skipped February). This means the results are more prone to random variation. Still, we learned something.

I germinated the seeds in what I call a “standard germination test setup”, a paper towel rolled around a chopstick, as in this blog. I checked the setup every night, and as soon as a seed put out a root, I planted it in potting soil. Then I later gave the seedlings away.

milkweed seed with root coming out

root can emerge, up to the length of the seed, in one day

milkweed seedling in plug tray

seedling planted

Incidentally, I found I could keep the seedlings in “suspended animation” by putting them in a sunny window in my unheated garage through the winter. They seemed to remain healthy, but stopped their pesky growth! The picture is of three batches started a month apart. Not growing, but unfazed by the cold. What a magnificent weed!

seedlings inside garage window

seedlings in unheated garage, in winter

Below is a chart of the total germination by month. If I’d had enough seeds for good tests, the counts might not have shown any variation at all. Still, germination was never less than 50%.

chart of germination percent by month

total germination by month

The chart of germination speed is even less instructive. Sometimes they started soon, sometimes after a delay. Sometimes they came up quick, sometimes drawn out. But not really over that much variation. Germination usually started the 4th day (rarely 3rd). No more seeds ever germinated after the 12th day.

chart of germination by elapsed days

rates of germination

All too much science never reports negative results. So here I admit, my hypothesis did not pan out. My experiment did not show anything about how to enhance milkweed seed germination. However, it clearly disproves “Cold stratify!”

Now, it is just possible this particular milkweed lost its chill requirement from being in cultivation. This is how it could work. There is always variation in plants. Suppose there were a big batch of wild-collected milkweed seeds, brought into a nursery to grow. Suppose, within those thousands, there were a few freak seeds that did not need any cold period to grow, while all the others did. Those few would be first to sprout. If the nursery person pounced on those, grew them out, and further propagated them, he/she might soon have a strain of milkweed that, genetically, did not need “cold stratify” while wild milkweed does. This is how a lot of crop seeds, such as beans and corn, have evidently lost any wild-type germination inhibition.

If you ever find wild milkweed with enough seeds, you can do your own tests. Cold treat one batch, don’t treat another, and then write your own blog!

Meanwhile, if you just want to get some milkweed growing, try planting your seeds at warm temperatures, and see what you get.

Asclepias speciosa

Here’s my original data, in case you want to check if it was the phase of the moon, or something!

start date count date count
10/6/2019 10/9/2019 1
10/6/2019 10/12/2019 3
10/6/2019 10/13/2019 4
10/6/2019 10/14/2019 5
11/6/2019 11/13/2019 3
11/6/2019 11/14/2019 4
11/6/2019 11/16/2019 6
11/6/2019 11/17/2019 8
12/6/2019 12/11/2019 1
12/6/2019 12/12/2019 3
12/6/2019 12/13/2019 6
1/6/2020 1/10/2020 3
1/6/2020 1/11/2020 6
1/6/2020 1/12/2020 7
1/6/2020 1/13/2020 8
1/6/2020 1/14/2020 9
3/6/2020 3/10/2020 2
3/6/2020 3/11/2020 6
3/6/2020 3/12/2020 7
3/6/2020 3/13/2020 8
4/6/2020 4/10/2020 5
4/6/2020 4/11/2020 9
5/6/2020 5/10/2020 1
5/6/2020 5/11/2020 4
5/6/2020 5/12/2020 5
5/6/2020 5/13/2020 6
5/6/2020 5/14/2020 7
5/6/2020 5/16/2020 9
6/6/2020 6/11/2020 1
6/6/2020 6/12/2020 4
6/6/2020 6/13/2020 6