what needs pollination?

hello

rather than ask what can i grow under insect net/mesh,
i thought it would be easier to ask what i can't - for purposes of pollination.
i plan to get some mesh to stop the insects and more importantly for me, the SLUGS!
so what needs pollination from the likes of bees and such, and therefore can't be permanently covered year round?
tomatoes - i got that one!
gg

Hi greengrass,

I don't think that the mesh would stop the slugs.

And tomatoes are self pollinating so they should be fine.

well what did you want to grow? maybe we could start there. lots of things don't need pollination unless you want to save there seeds like broccoli, cabbage, kale, swiss chard, spinach, you know the leafy things.

pryz123 wrote:Hi greengrass,

I don't think that the mesh would stop the slugs.

And tomatoes are self pollinating so they should be fine.

well what did you want to grow? maybe we could start there. lots of things don't need pollination unless you want to save there seeds like broccoli, cabbage, kale, swiss chard, spinach, you know the leafy things.

I can't see how mesh would stop slugs either, they would just go under it.

Ah the myth of the "self pollinating tomato" rears its head once again. Tomatoes are self fertile, but they definitely need help to pollinate. Try growing them in a greenhouse and you'll see.

Root crops and greens don't need bees for you to make a harvest - they do need them at the seed grower's place though.

And crops like squash, melons and cukes can be kept under cover most of the time, and opened for a couple hours each day, about the time the dew is dry, so bees can get at them, or you can hand pollinate.

Pollinator, thanks for correcting me on the tomato self fertile thing. I thought they were self pollinating because the fruit usually is true to plant, if you save your seeds.

pryz123 wrote:Pollinator, thanks for correcting me on the tomato self fertile thing. I thought they were self pollinating because the fruit usually is true to plant, if you save your seeds.

The tomato bloom needs a mechanical bit of help to pollinate itself... usually the wind, but bees can help if the bloom is not isolated.

Anything with a flower needs a pollinator.
Tomatoes and peppers are self-fertile so you can keep them covered but you'll have to tap the flowering branches now and then so the pollen can escape and settle on the flowers.

Things you can cover would be:
cabbages, broccoli, cauliflower, Brussels sprouts, Chinese cabbage, Bok Choi, all the greens, spinach, lettuce, herbs, carrots, the onion family, chard, spinach, parsnips, beets, turnip and all the other plants that don't make flowers until they are dying and going to seed. I can't think of more right now but you get the picture.

pryz123 wrote:Pollinator, thanks for correcting me on the tomato self fertile thing. I thought they were self pollinating because the fruit usually is true to plant, if you save your seeds.

The wild progenitor of the tomato is pretty much cross pollinated. As the tomato was taken around the world, its primary bee pollinator was not taken with it, so we have bred a tomato that is basically self fertile. Now this is a defect in Nature, but we breed it to suit our purposes. And it makes it easier to get the tomato pollinated.

Even yet, the anther of the tomato is a hollow tube and it had the pollen grains on the inside - as opposed to most flowers which hold the pollen grains on the outside of the anthers. And these pollen grains are tightly held, so no pollination can occur unless something helps move the grains.

The best possible pollination (resulting in the most fertilized seeds and the largest, best flavored tomatoes) is from a sonicating bee, such as a bumblebee. The stigma on many tomato varieties is recessed within the corolla, so the bee doesn't actually touch the stigma.

Rather the bee pulls the flower down, so the corolla is vertical, then it vibrates its wing muscles, shaking the flower in resonance with the flower itself. This releases masses of pollen grains. Some of these will strike the pistil as they drop, others strike the bee on the belly and bounce right back up from the vibration, to strike the stigma.

You can show this effect by touching a tomato flower stem with a vibrating tuning fork (Middle C) to watch the spewing of the pollen grains.

Wind, or your tapping on the flower, can release pollen, but never as efficiently as a sonicating bee. At any rate the tomato flower is not doing this by itself, so it isn't self pollinating. You can say it's self pollenizing (to pollenize is to provide viable pollen, which it is, since it's self fertile).

Some of the oldest tomato varieties we have, such as the yellow pear do not have the recessed stigma - the stigma is said to be exerted, that is, it sticks out beyond the flower corolla where it can be brushed by a visiting bee that carries on its body pollen from another tomato plant. Thus the older varieties we have are more akin to the original progenitor, and are much more likely to cross.

If you are saving seed, the amount of outcrossing you are likely to get is a combo of the closeness of other varieties, the number of visiting pollinators, and most of all, whether the flowers have exerted or recessed stigmas.

Look at the flowers on your tomatoes. It's pretty easy to see which ones have stigmas that stick out and which are recessed.

Pollinator, WOW! Thanks for the detail. That was so nice of you to give all that info. I love learning. especially gardening stuff.

hey thanks pollinator & quiltbea
some great info there!
the slugs won't get in as there will be a 2"x2" wooden frame lying on the top of the 4x4 beds, trapping the mesh, which will stop them crawling under.
and the mesh size is small enough for flies etc.

i will be growing mainly greens, lettuce-cabbage-spinach etc.
but also beets-onions-carrots, so i should be ok.
thankyou folks
gg

FYI I moved some of these posts to the slug thread to try and retain the topic on pollination.

Camprn,
Do you have a link to which slug thread. I may have missed some stuff while gone today.
Jo

Little Jo you can find the slug thread either in the latest topics list or in the pest forum.