zone 13, Phoenix AZ and planted on March 11th... at this point (74 days) the
vines are just 2' long at most, there are blooms on the vines but no fruit.
They get watered twice a week and get direct sunlight from morning to 4PM. I
would expect them to be ripe by 90 days.. What do you think? I still have
time to plant something else there if they aren't going to work out. This is
the second year I've been trying to get them to grow.
I do not know the soil or climatic conditions in your area so I am able to make
only general comments.

1. I planted in early April over a two week period. Plants are now vining. Most
years and I don't expect this to be an exception I pick the first ripe melons
by the Fourth of July.

2. The time frames stated are for comparison. An 80 day melon should ripen
earlier than a 90 day melon, but cool weather heavy soils etc slows down the
growth process considerably. As a result a watermelon planted very early may
bear at the same or later time than one planted later under optimum conditions.
I learned this when I tried to push the season and had to replant a lot of
missing hills. The replants finish at the same time as the originals.

3. I know Arizona is supposed to be desert like but twice a week watering?
Despite popular conceptions watermelons really do not like a lot of water. I
grow without irrigation and they are among the most drought resistant veggies I
grow,
Deep watering on an extended interval is far better than repeated shallow
watering.

4. Lastly watermelons will grow happily in beach sand but sulk in heavy clay
and mud soils.