Zucchini turning yellow, not growing

Hi there, I have a Zucchini plant that appears to be growing well (nice large, green leaves). I got 2 nice zucchini's off of it, but the next 2 only grew about 3 inches and then turned yellow. I read a bit about pollination, but that's not the issue if the fruit has started to grow, correct? Also, we have tons of bees in the garden (my dog, the "bee chases" has the stings to prove it!   

It could just be a fluke and I'm not giving the plant enough time to really get established.  Oh, and it case it matters, I'm in San Diego (days are hot/nights mild - ~ 82/55)

Thanks!

Can you post a photo of the plant? That would help.

The fruit can start to grow, but be poorly pollinated. Often the first few days growth of the fruit/first few inches look fine, and then the end never fully forms, and appears to go yellow and pinched. So pollination could well be the problem, even though for your first two zucchini, it wasn't.

If the leaves look pretty healthy then that is not uncommon to lose the first few fruits due to poor pollination. Sometimes the boy flowers are a little slow to show up. Go figure.

San Diego is a delightful place to garden.  At the base of every female squash flower is a small fruit.  If it's not pollinated or pollinated enough, it will still grow for a day or few, then turn yellow and die.  It takes a minimum amount of pollination for the tiny fruit to grow into an edible squash.  A good pollination produces a nicely shaped fruit.  A fruit that was pollinated enough to grow but not fully pollinated, will have an odd shape like a waist or longer on one side than the other.

tiffanybrenner wrote:Hi there, I have a Zucchini plant that appears to be growing well (nice large, green leaves). I got 2 nice zucchini's off of it, but the next 2 only grew about 3 inches and then turned yellow. I read a bit about pollination, but that's not the issue if the fruit has started to grow, correct? Also, we have tons of bees in the garden ...

If a few grains of pollen are delivered, the fruit may well start to grow, then abort, or grow and be deformed. The key is whether enough grains of pollen are delivered - it takes two grains for each incipient seed, one for the embryo and one for the seed coat.

Having "tons of bees" is good, in general. But are they working on the squash? You need many visits to the squash blossom to get enough pollen. And in hot weather, there's only a narrow window in the morning for this to happen, before the flower wilts and is no longer fertile.

In my own garden, honey bees are busy working on the cucumbers and melons, but they don't touch the squash, as they are finding better. The little squash bees are there before daybreak, visiting the squash blossoms, until around 8 a.m. and then the bumble bees take over for the second shift, so my squash is being well pollinated.

Sometimes people plant rich pollen and nectar flowers "to attract bees."  That is an inadequate goal - you may attract them right past the squash you want pollinated, to go to the flowers you planted to attract them. In my garden there is a wild invasive weed called Florida betony in great abundance. It's a mint, so it's highly attractive to many bees, and it drew the bumble bees away from my garden veggies. Fortunately I do have squash bees, which *only* work squash, so I was covered there. But the bumble bees were needed on my tomatoes, and I had to hand pollinate with a tuning fork, to stop the blossom drop.

Squash bees are extremely pesticide sensitive, so you may not have them, depending on pesticide practices in your area. Mosquito spraying, or yard-fogging neighbors can decimate pollinator populations. It can often affect one species of bee more than another, depending on which flowers they are working, the hours they are working, etc.

You may not see squash bees, as they are early morning workers. If you have them, you will sometimes find the males holed up inside closed flowers, where they sleep. Then, in the morning, they will chew their way out to look for the females comeing to the new blossoms.

Sorry for the delay in follow-up and responding to all of you who were kind enough to post a response to my zucchini issue (I was derailed for a few days with a sick infant - all is better now   )

So the pollination thing - specifically having under developed zucchini's and not being pollinated enough makes complete sense. I realized after your responses that I had very few blossoms at all. In the past 4-5 days I went from 1 open flower to about 10. So hopefully now that the plant is developing more the bees will get to work! 

Thanks so much!