Tap root depth

Logically, it seems to be THE most important mechanism early on in the grow cycle, but looking out 4-8 wks, when all the rest of the root system is in place, how important is it that the tap root have plenty of depth continue its downward journey, in the scheme of things?

The freedom for it to travel vertically: is it of no consequence when it touches bottom and has to turn one way or another?

I just pulled an exterior puny plant 8 weeks old and its tap root must have hit hard clay or other impenetrable mass and turned sideways but the tip didn't like it much. I looked kind of withery, and since the plant didn't do very well, (genetics, or just too little sunlight being in the back of the other plants?) I was wondering if I should opt for deeper planters, columnar ones, three feet deep when I begin my interior grow in the spiffy new grow room with 7 ft height.

Read somewhere that the height of the plant above ground is roughly equal to the depth below ground. And that would mean a 4 foot plant would like it best with a 4' taproot. (assuming no LST or HST, supercropping, fimming and lollypopping).

Here is the thing about roots.... they grow in the direction they can. They will take the shape of the container. If you are growing out doors, you should probably give it enough depth and width to grow some large root balls. Roots do not just grow down, they grow out. They probably grow out more than they grow down so they can get as much water as possible. Give it three feet of width and depth and it will have plenty of space to grow a nice big root ball.

I heard plants have an "equal mass" of roots compared to the above growth.. Not that the taproot equals the plant height. Input anyone?? And also.. How deep will a canibis taproot go?

I have read that there is so little oxygen available below 24 inches that cannabis roots will not exceed this depth and the mass of roots will only rarely go below 18 inches. Check out the science behind smart pots Dblbogey.

Skeeterass said:

I heard plants have an "equal mass" of roots compared to the above growth.. Not that the taproot equals the plant height. Input anyone?? And also.. How deep will a canibis taproot go?

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Nah, they'll produce much more above ground then they have below ground. Of course, if you push that balance too askew you'll have rootbound plants that need watering every day if not twice and you'll constantly be fighting nutrient issues, but nevertheless there is little mass in a root ball compared to a flowered top (roots are small and light). Volume or space occupied might be a little closer than mass, but I've still seen most plants have considerably more above the dirt than below the dirt.

Not sure where this "advice" comes from, perhaps people flowering 3' plants in 30gal pots?

Much depends on nutrient availability. Check the Yogurt Cup Grow Contests. Plants like air in the soil, so they will spread roots wide in the upper soil, which allows them access to more water. Good luck. -granger

Roots Dymystified by Robert Kourik is an awesome read. Check it out from your local library, then like me buy it for its greatness.