From research I've done in the past, for typical grapefruit varieties, the percentage of seeds that are nucellar tend to range somewhere between about 70 to 90 percent. If the seed is nucellar, that would mean it's an exact genetic clone of the parent, so definitely "true to seed".

However, there's still the matter of it not being grown in rootstock. If a tree is growing on its own roots, rather than a different variety of rootstock, it's going to behave very differently. It will end up growing much bigger, but it could also take 4 or 5 years longer before you see fruit.

(Some of the effects of growing on its own roots could be negated by it being inside a container, since containers restrict the root growth)

If the tree is already 20 years old by now, it should be capable of producing fruit if it gets the proper conditions. Depending on the size of the container, it might need to be repotted into a slightly larger container. (To do this you should trim the outer roots)

There are many other things to consider, and it wouldn't be possible to go into it all here. You might want to get a spray for spider mites and check up on the leaves regularly for the first few weeks, and also make sure the area in the home is not going to get all dried out by warm dry air from a central heating system.

Actually grapefruit is the worst choice to grow from seed as a container plant. A seed grown tree can take 10 to 15 year to fruit, quicker when grown in the ground outside. Getting only water and no fertilizer applications, also caused the tree more difficulty, and greatly delays its fruiting and growth. If you have a personal feeling for the tree, than continue to care for the poor thing. Otherwise, purchase a grafted tree from a good supplier and receive fruit in just a few years.

Thank you both for taking the time to write. Your responses are very helpful! I will take it under consideration and decide from there.

If you like grapefruit, what do you have to lose? If I liked and could eat grapefruit, I would take it as a personal challenge to see if it would flourish under my care. If you don't care for it at home, what will happen to it at the office? I am curious how the tree looks after being inside for so long.

You didn't say how tall the tree was but trees have branch node counts as to when they will fruit. Only the tree knows how many nodes it has to grow to bloom. A continuously pruned tree from seed can possibly never bloom because of that. But if if you were to take cuttings off the top the cuttings would remember their node count and you could eliminate several feet from the process and grow an unknown variety of grapefruit on its own roots. Might make a nice houseplant(s) as you wait.

Just to clarify, the tree in question is not in a building I work out of fulltime, but I'm in periodically. I made a special visit there this morning to get more info on it, and found it in a sorry state. It clearly went a while without water. For how long I do not know. However the soil was damp, so someone is trying to resuscitate it. I let the guys in the building know that if it makes a recovery, I would take it home and give it a better chance. It's pot is definitely too small for a tree about 6 ft tall. It goes up a couple more ft than what you can see in the pic. This is the best photo I could take.

I vote for saving it. It can be a beautiful tree once it gets some TLC. :)

I vote save it. I bet with some care it would look beautiful!

Honestly, I wouldn't since I don't have room for things like that indoors (can't be put outside in that zone). Especially if the seed grown tree may never bear unless it gets 12 feet tall (or maybe 6 feet wide) for the required node count. But you could breath some life into it provided you know what your getting into. It would be a good learning experience

If you wait for a "recovery" headed by somebody else by just watering, you may as well write it off. Take it home now while there is a chance, in a week or two some inexperienced person may have killed it.

By recovery, what I meant was for it to show some signs of life. I'd hate to go through the trouble of lugging it home if it's already dead. Although if you think it's still alive, I wouldn't mind making the effort. Is there any way to know if it's still alive without waiting for new leaves to emerge? Some of the branch tips were brittle, but I didn't investigate much further. What size pot would be suitable for it?

-Chris

Before doing any repotting, I’d water it and wait for signs of life. Let it revive a bit. Once you see some life, in the spring, then repot it.

Any idea how long it should take to begin seeing new growth?

I'd guess a few weeks since its settling into a new environment

Actually I have not brought it home yet. All the leaves have dried up and are dropping. If it's still alive, I was wondering how long it would take to begin sprouting new leaves. I was waiting to make sure it's still alive before I transport it because getting it home won't be that easy given it's size.

If you wait and don't change its conditions, it will likely die

You seem reluctant to try saving the tree. Why? If you bring it back to life, then you can always sell it.

scratch under the bark, if you see some green, it may still survive. if its all brown, i think its a goner.

I have a bad back (scheduled for an MRI this week in fact) and a small car, so don’t want to lug home a dead tree. I can’t see that waiting a couple of weeks to see if it‘s still alive will be deadly. It’s been in this exact spot for 20 years and survived. I will make sure it does not go without water again. The damage to the tree occurred prior to me writing this post so conditions have only improved since then. If it is still alive I will bring it home and gladly give it a chance.

I understand Chris. As long as you make sure it gets watered, why lug it home till you know if it has a chance. Let us know how it works out please.