Is there any way I can get tighter internodal spacing on a plant? I’m growing White Widow x Big Bud, using the Sea of Green method. My clones are 3"–5" tall when I put them into flowering. By the third week, they are reaching 12"–16" tall, with a lot of internodal space.
I have two 400w high-pressure sodium lamps covering a 4' x 8' area. The light stays about two feet above the plants. I keep the temperature between 70?F-80?F and humidity between 50% and 60%, and the garden is well ventilated. I water about once a week and the plants are healthy.
Both plants have relatively short internodal spacing and fill in with calyx-heavy buds in between. They will shoot up toward the light as they mature. Clones are growing about 10 inches in three weeks, at a rate of just under a half-inch per day. This is a healthy growth rate, not too fast or too slow. Plants could be stretching between internodes because of too much yellow light and not enough blue light, or it’s possible plants are crowded too closely together and receive too little light. You could change lamps from HPS to metal halide, which would provide more blue light and reduce stretching. You could move lights closer (12"–18") to plants so that they receive more light. Move plants a little further apart.
My feeling is that everything is just fine in your room except for the lights being a bit far away. Move them closer to the plants. Do not move them closer than 12", to avoid burning leaves. Clones should be ready for harvest when they are about 24" tall. Light can easily penetrate to the bottom of foliage. All is well in your garden!