Choosing a plant for the proposed bolting experiment

In my previous post I speculated about devising an experiment to test whether the "bolting" of plants, i.e. the tendency of plants to shoot up vertically and set seed early rather than developing leaves and roots as desired for harvesting, can be hindered or prevented by some natural means. The plant that would be best for conducting such an experiment would be one that remained small throughout its life cycle, so that a large number of the plants could be grown in one flat. It would have a short life cycle, preferably less than a month, so that the experiment could be performed quickly. It would have an obvious difference in growth habit between its "unbolted" and "bolted" state, as seen (for example) with brassicaceous crops such as cabbages and turnips. It would have to grow essentially self-contained and compact, not sending out runners or suckers that pop up some distance from the plant. And it have to be a plant that's easy to get hold of.

Shot-weed photo from MulchMaid blog

I discussed the matter with a friend of mine, a professional gardener, and he suggested that "shot-weed" would be a good choice. Shot-weed is one of several common names for Cardamine hirsuta, a brassicaceous plant somewhat related to watercress, a small and highly invasive plant that produces long, thin seed pods after only a few weeks of growth at most. When the pods are fully developed, even a slight touch causes them to pop open, sending their seeds flying in all directions, hence the name "shot-weed". I've seen this for myself when pulling weeds in various gardens. Before setting seed, however, shot-weed forms a compact rosette of small leaves (see photograph above).

The difficulty is that shot-weed is one of those things that's easy to find when you're not looking for it. I've probably pulled up hundreds of these plants without thinking about it, yet when I'd actually like to collect some seeds from it, I can't find any. And it's not like you can buy shot-weed seed at the hardware store.

Of plant seeds easy to purchase off the shelf, I thought that radishes, Raphanus sativus, would be a good choice. They germinate quickly and also set seed quickly but would take up more room to grow than shot-weed. My gardener friend thought it was a logical choice.

Now I need to figure out where I can get room to conduct this experiment, if at all possible, and how much room I'll need.