Container Culture

Often bulbs are grown in containers or pots. Below are links to some relevant wiki pages.

Container Culture Temperature investigates the temperature of bulbs in pots.

Growing Medium compares media useful for growing geophytes.

An interesting PBS list post from Dylan Hannon on matching plant sizes to pot sizes.

There are many different sorts of pot - one division is between plastic pots and clay (also called terracotta) pots. Plastic pots are impervious, whilst clay pots are porous allowing water and air to pass between the contents and the outside. Clay pots may also help keep the temperature inside the pot more stable. Traditional pots are round, more modern (and usually smaller pots) are square. The advantage of square pots is that more can be packed into a given space.

There are special extra deep pots, sometimes called "long toms", "palm pots" or "tree pots", the advantage of these for bulb growing is that the drainage is better, the compost at the top will be drier than in shorter pots. Other specialist pots are available, for example pots with no bottoms (again for better drainage), pots with holes in the sides to improve root formation (air pots), pots with transparent sides. You can make your own pots from old food and drink containers.

When someone talks about a "5 inch pot", do they mean 5 inches high or wide. Photo 1 shows a basic thing about pots, they're usually as wide as they are high, so it doesn't matter which dimension you use. However extra deep pots are available as shown in photo 2. The pots in photo 1 are terracotta, those in photo 2 are plastic.

The photos display another common feature of pots, they have holes in the bottom to let excess water drain. An old belief is that drainage is improved by filling the bottom of pots with "crocks" (pieces of broken clay pots) or stones. This idea is now considered wrong (see this discussion). It is still OK to use a piece of old pot to make sure the hole does not get bunged up or to keep the potting medium in; however a piece of mesh, gauze or other material that allows the escape of water is better.

Sometimes there is confusion between people using heights and those using volumes to describe the sizes of containers. The tables below convert between the two. They assume height equals width and a 7 degree angle for the pot sides.

Click to see table of heights and volumes of round pots...

Click to see table of heights and volumes of square pots...