I had one small oxalis, now I have 3 huge ones. They will fill out the pot until there is no space left. Once that happens new growth tends to be spindly and weak. You are overthinking it, once it gets too big just divide it.

The PRIMARY consideration when trying to determine appropriate pot size is your soil choice. Some plants are over-potted in a half cup of soil, while the tiniest of seedlings can be grown in a 55 gallon drum full of soil if the soil is appropriate.

Grow your oxalis until Oct, then let it dry down & put it in a cool spot (basement). Take the planting apart in late Apr or early May and repot the number of bulbs you want in an appropriate soil. Repeat that annual cycle and you'll be happy with the results - fertilize regularly too, btw; and DON'T use a 'bloom-booster' type fertilizer.

Al

Thank you, kuerbiskopf. I suppose I was overthinking it, but this is my first planting. My question stems from wondering how much room do the bulbs need to propagate and flourish. Some species may like to be cramped while others don't. I ordered 15 bulbs. Is it OK to plant them all in a 6" pot? Depth of pot is 4".

Al, thanks! I am all familiar with your soil expertise. I am a "secret fan" and I get it. AND I will not use a bloom-booster. I got some Superthrive. How do you feel about it?

Lol - you asked ...... I wrote this about 10 years ago - before Linda Chalker-Scott PhD wrote her debunking piece about it. They're very similar

Superthrive
or Superjive

The
question regarding the value of Superthrive as a miracle tonic for
plants is often bandied about in horticultural circles. Over the
years, I had read claims that ranged from, “I put it on my plant,
which had never bloomed, and it was in full bloom the next day.”
to, “It was dead - I put Superthrive on it and the next day it was
alive and beautiful, growing better than it ever had before.” I
decided to find out for myself.

If
you look for information on the net, you will probably only find the
manufacturer’s claims and anecdotal observations, both so
in want of anything that resembles a control. Though my experiments
were far from purely scientific, I tried to keep some loose controls
in place so that I could make a fair judgment of its value, based my
own observations. Here is what I did, what I found, and the
conclusions I made about any value the product Superthrive might hold
for me.

On
four separate occasions, I took multiple cuttings of plants in four
different genera. In each case the group of cuttings were taken from
the same individual plant to reduce genetic variance. The plant
materials I used were: Ficus benjamina, (a tropical weeping fig) Luna
apiculata (Peruvian myrtle), Chaenorrhinum minus(a
dwarf snapdragon), and an unknown variety of Coleus. In each
instance, I prepared cuttings from the same plant and inserted them
in a very fast, sterile soil. The containers containing half of the
cuttings were immersed/soaked in a Superthrive solution of
approximately 1/2 tsp per gallon of water to the upper soil line. The
other half of the cuttings were watered in with water only. In
subsequent waterings, I would water the “Superthrive batch” of
cuttings with a solution of 10 drops per gallon and the others with
only water. The same fertilizer regimen was followed on both groups
of cuttings. In all four instances, the cuttings that I used
Superthrive on rooted and showed new growth first. For this reason,
it follows that they would naturally exhibit better development,
though I could see no difference in overall vitality, once rooted. I
can also say that a slightly higher percentage of cuttings rooted
that were treated with the Superthrive treatment at the outset. I
suspect that is directly related to the effects of the auxin in
Superthrive hastening initiation of root primordia before potential
vascular connections were destroyed by rot causing organisms.

In
particular, something I looked for because of my affinity for a
compact form in plants was branch (stem) extension. (The writer is a
bonsai practitioner.) Though the cuttings treated with Superthrive
rooted sooner, they exhibited the same amount of branch extension. In
other words, internode length was approximately equal and no
difference in leaf size was noted.

As
a second part to each of my “experiments”, I divided the group of
cuttings that had not been treated with Superthrive into two groups.
One of the groups remained on the water/fertilizer only program,
while the other group was treated to an additional 10 drops of
Superthrive in each gallon of fertilizer solution. Again, the
fertilizer regimen was the same for both groups. By summer’s end, I
could detect no difference in bio-mass or vitality between the two
groups of plants.

Since
I replicated the above experiment in four different trials, using
four different plant materials, I am quite comfortable in drawing
some conclusions as they apply to me and my growing habits or
abilities. First, and based on my observations, I have concluded that
Superthrive does hold value for me as a rooting aid, or stimulant if
you prefer. I regularly soak the soil, usually overnight, of my newly
root-pruned and often bare-rooted repots in a solution of 1/2 tsp
Superthrive per gallon of water. Second, and also based on my
observations, I no longer bother with its use at any time other than
at repotting. No evidence was accumulated through the 4 trials to
convince me that Superthrive was of any value as a “tonic” for
plants with roots that were beyond the initiation or recovery stage.

Interestingly,
the first ingredient listed as being beneficial to plants on the
Superthrive label is vitamin B-1 (or thiamine). Growing plants are
able to synthesize their own vitamin B-1 as do many of the fungi and
bacteria having relationships with plant roots, so it's extremely
doubtful that vitamin B-1 could be deficient in soils or that a
growing plant could exhibit a vitamin B-1 deficiency.

Some
will note that I used more of the product than suggested on the
container. I wanted to see if any unwanted effects surfaced as well
as trying to be sure there was ample opportunity for clear
delineation between the groups. I suspect that if a more dilute
solution was used, the difference between groups would have been even
less clear.

It
might be worth noting that since the product contains the growth
regulator (hormone) auxin, its overuse can cause defoliation, at
least in dicots. The broad-leaf weed killer Weed-B-Gone and the
infamous “Agent Orange“, a defoliant that saw widespread use in
Viet Nam, are little more than synthetic auxin.

Al

LOL....I did ask!!!! Thank you for sharing your wealth of knowledge. Degree or not, you are such an avid horticulturist! May you never loose your desire to explore, learn, and share. BTW, take a look at her go in less than a week!

Strong work! I hope your enthusiasm holds and your desire to learn grows. Those attributes will always serve you well.

Al