Everytime I start broccoli after a few weeks are past the stems get long and, as thay say, leggy. Why is it that greenhouses have plants with nice straight thick stems? What's the trick to preventing this?
The light is not bright enough for them. They need more light. Try setting a fluorescent bulb just a few inches above the seedlings and that should correct the issue.
We have a parakeet that we feed broccoli heads. I clean the cage outside and have noticed broccoli plants where I clean the cage! I usually just throw the spent heads on the ground. Is it the florets on the heads that are sprouting? We are going to move the plants to a garden area to grow.
Most likely, one of the heads had enough energy left to flower and produced seeds and now they are growing. It is not unheard of for some plants to make a "last ditch" effort to produce seeds, even after they have been cut from its roots. Have fun with your broccoli volunteers!
I have been growing broccoli for a couple of months now. The first head I cut off was not as firm as the ones you get in the grocery store, but it was still decent. I thought maybe I didn't let it go long enough, so the second head I let go a while longer. The second head was pretty loose and fluffy. I even let it go so long that I found one bud opening to a flower. What can I do to make the heads firmer?
The heads are loose because the plant is starting to bolt. Keeping it from bolting will keep the heads firmer. This article will help:
https://www.gardeningknowhow.com/edible/vegetables/broccoli/bolting-broccoli-growing-broccoli-in-hot-weather.htm
I planted broccoli seeds three weeks ago and they look like thread. What did I do wrong? Will they get bigger?
They do not have enough light. Add more light by either putting them in a brighter window or using a fluorescent light to supplement the light the seedlings have.
I am undergoing a project of growing broccoli in a poly house, so the temperature here is around 37-47 degrees Celsius. Will I get any fruit/vegetables in this condition? What else should I do to protect my crops?
That is far to warm for broccoli. They need cooler temps, especially for the soil. Otherwise, the plants will bolt and be inedible. This article will help:
https://www.gardeningknowhow.com/edible/vegetables/broccoli/bolting-broccoli-growing-broccoli-in-hot-weather.htm
I have some early voluntary broccoli plants growing like gangbusters. It has started to have yellow blooms. I seem to remember that I need to cut these off. Is that correct?
Once they start to bolt, the flavor goes south on them. You can cut them off, but the crop from the plant will be poor. Here is some information on keeping them from bolting:
https://www.gardeningknowhow.com/edible/vegetables/broccoli/bolting-broccoli-growing-broccoli-in-hot-weather.htm
I live just south of Atlanta and two of my broccoli plants have giant flowers. Should I cut the flowers off and hope for side heads of broccoli on the same plant, or should I just give up on those plants? Also, I think a head on another plant is ready to be harvested, but it is still only three inches across, should I harvest it?
The following articles should be of some help to you:
https://www.gardeningknowhow.com/edible/vegetables/vgen/what-is-bolting-what-it-means-when-a-plant-bolts.htm
https://www.gardeningknowhow.com/edible/vegetables/broccoli/how-to-grow-broccoli.htm
https://www.gardeningknowhow.com/edible/vegetables/broccoli/harvest-broccoli.htm