Question
Dear Tom,
I have to date grown eight Avocado Trees from seed, various varieties. Six of them now are over a year old and potted in 16" pots, they are on average about 3-4 feet tall and branching well.
I wondered, can I plant them in the ground as a "grouping" even though they are differing varieties?

Answer
Hi Christopher,
Thanx for your question.  You cannot plant your avocado trees outdoors unless you live in a relatively frost-free part of the world.  Adult avocado trees will tolerate light frost but not sustained, continuous frosts.  Because I don't know you general location, I felt like I should put that information out first.  If you do live in a mild climate, you may plant the trees in a grouping.  Bear in mind that they will cross pollinate each other.  And one does need more than one tree to set good fruit which won't happen for another 4 or 5 years.  If the seeds you planted are from store-bought fruit, you are probably growing seeds from hybrids which means that the resulting plants will bear little or no remsemblence to the parent plants and in most cases the fruit and plant will be inferior to the parent plants.  However, that does not mean the fruit and/or plants won't be acceptable.  I hope this helps.
Tom