When to start pruning?

One of my 2 plants is at its 2nd week in veg. She's 4 weeks old today exactly and is beginning to look pretty bushy. I am thinking I should maybe begin to prune but it's my first grow and I don't want to eff anything up. Hoping for a decent yield. She looks very healthy and green so far no signs of any deficiencies, besides one random yellow spot on one of the leaves.

Thanks in advance for any advice.

With being your first go and just 2 plants I'd recomend pinching the very tops about this time. Then depending on how long you want to veg them, based on avail. space and final yield desired, you could again pinch the multiple tops that result in another 3 wks or so. Keep in mind that every time you pinch off the tops the growth hormone disperses in the plants and is redirected to the upper remaining brances, which slows growth overall for about a week to 10 days. And thus it's not a timely good idea to do this right before you switch to the 12/12 bloom cycle for best results. Bud development can be stunted, yielding smaller scattered clusters than if you let them veg untouched for at least 2 wks before you switch to 12/12. I'm a SOG man myself. But with just 2 plants I'd go with what called, "Supercropping" from an old HT article. Essentially what I just described. The main advantage to SOG is one can avoid the time pinching and developing side brances large enough to support a sizeable yield from just a few plants. Besides the main top cola on an untouched plant yields a more massive and consistently potent bud ratio yield per sq. meter than any other method, where usually more branching yields a higher percentage of duffy and less potent buds on side and bottom branches.

There is another technique that produces similar results without having to pinch the tops, and so losing speed of development over time. By "training" the top, bending and/or tying the tips w/ twisty ties or string (twisty ties are easier to use, bend and simply hook ends around branch crotches) so that no one part of the plant is above or closer to the light than most of the rest of the branch's tops. The idea is to form an even hedge-like density of veg growth as they begin to bloom. This was the method I used for years before it was common knowledge it was possible to get potent yields off plants less that 4-6 mos old and 6-8 ft tall.

i prune to suit my lighting specifics and veg times. generally if you veg longer you can get a bushier plant that produces more. i veg for shorter times and cut out side shoots to produce a lg single cola. but i suggest you experiment with dif methods to become framiliar with them.