It could have 2 meanings. First, & probably the answer you're looking for: it means to reduce the # of seedlings growing in a given space to insure that as the plants mature they are not directly competing with each other for vitals (water, sun, nutrients, sunlight).

It could also mean reducing the number of growing points on a plant. It could be thinning of branches, blossoms, or even fruit. This might be done if a single large bloom (mums, dahlias) or larger fruit or blossoms are desired instead of many small ones (growing a giant squash or pumpkin).

Al

The best way to thin a batch of plants growing too close to one another is to snip off the unwanted ones ar ground level, or just pull up those that you don't want.
Linda C

On the other hand, if only a few seeds were sown initially, you'll save a lot of time and energy. Please check out the Square Foot Gardening forum. It truly is an economical way to garden - financially and physically.

Have fun. :-)

Here is a link that might be useful: Square Foot Gardening

Thank you all for your replies. If I understand your posts correctly,t

Thank you all for your replies. If I understand you correctly, thinning out is simply pulling off a seedling and throwing it out, right? if so, then why do gardeners sow many seed to begin with?
Another question please...Is it advisable to throw a bunch of seeds together in a hole for them to sprout, like sunflower seeds? The appearance of the plant is nice to look at.
Also..How much space should there be between one seedling and another and why is that important? Thank you all.

N.B Sorry for the above post.

The accepted spacing for seeds depends entirely on the seed itself *and* the method of growing. I don't know where the practice of over-seeding began - it's been around a long time. Some people still do it, either from not realizing there is another way, or because they are concerned that some seeds won't sprout. There is an old corn-planters chant: "one for the cutworm; one for the crow; one to rot; and one to grow" which expresses the expectation of common problems and deliberately over-seeds for each problem. The present (and very sensible) method for the average seeder is to space them just far enough apart to grow - if you are starting the seeds early in seedling flats, they will be spaced just enough to grow up to 4-6 true leaves and then be transplanted. If you are direct-sowing into a garden bed, then you space far enough for each plant to have room when it's grown up.

Some seeds are as fine as dust - no way can you space them appropriately which means some sprouts will be crowded together. If you are growing these in a pot or a flat, it's easiest for the sproutlings if you snip the extras out so the roots of the remaining plants are not disturbed. Sometimes there is space between the seedlings but they are still too close together; you can carefully lift the extras and plant them into another pot or flat.

Very large seeds such as sunflower are usually planted directly into the ground where they are to grow -- you can plant one seed per space because you will only want one plant per space. Check the square foot gardening forum for more help on appropriate spacing for different seeds which are direct-sown into their growing beds. (I think their FAQ has a list, as well.) BTW, some "seeds" such as beets are actually a sort of cluster - put one into the ground and you're gonna get 3 to 6 plants in each space. Most folks snip the extra plants when the leaves about 2" - for use in salads!

You can plant several seeds in one hole....you will have a cluster of plants....and they may not get as tall as other wise. I often have squirrel planted clusters of sunflowers in my gardens.
I know of no plant that grows more than one plant from one seed......some plants grow in clusters of leaves ( like beets, lettuce, kale , daisys to name a few) but they are one plant.
Linda C

Never planted any beets from seed, Linda?

True: each plant does comes from one seed. Also true: the beet "seeds" gardeners plant are not actually single seeds, but a cluster of seeds. Therefore, although the gardener thinks he planted one beet seed, he actually planted one "cluster" and as a result will have several beet plants come up at the site of each single beet-seed-cluster. I think this is one reason why commercial farmers so often use pelleted seed, and according to what I've read, even after pelleting it's possible for 30% of the drills to be multi-plants.

See link, scroll about 1/3 down to "spacing" info.

Also true of course, that several seeds of anything can be planted in one hole. Not particularly good for any of the resulting plants, but possible.

Here is a link that might be useful: U of Arkansas on beets

Lindac, not that is has anything to do with this posters questions, but citrus, mangos, others (more common in fruits and nuts) will sprout two plants from the same seed -- polyembrionic.

A few months ago, someone posted a picture of a hellebore that was clearly sprouting two seedlings from the same seed...he didn't get much response, I suspect not many of us had seen that with hellebores....

Yep....have grown beets....but never saw more than one plant per seed, but frankly, I grow them for the greens not the beet.
But if they grow several plants from one seed, aren't the beets produced in a cluster and not perfectly round?
Never knew so many things were polyembrionic....but do remember being in the tropics and seeing nuts with more than one shoot emerging.
Live and learn!
Linda C

Yep, beet seedlings left in a cluster will mostly have rather strangely shaped roots, which is why gardeners are always told to thin them to one plant. Thinning is not as important if growing them just for the greens, although I would expect healthier plants if the greens-type were also thinned to one. OTOH, I rarely bother to thin chard, which has the same growth habit, possibly because like lindac, I think of it for the leaves, not for the roots.

Beets are not polyembrionic, but the gardener's perception of the seed makes them seem that way. We have to remember to differentiate the actual seed from the common casing: if an orange were the size of a beet seed-cluster we would be tempted to call the whole thing a seed, yet only when the rind is removed can one find the true individual seeds. If a single one of those interior seeds produced two [or more] separate plants, then it would be considered polyembrionic.

I greatly appeciate your input, all of you. Once you have a seedling, how to water it and how often? I have noticed when I water the leaves, they turn yellow.
Sorry so many questions, just can't help myself. All of a sudden I became in love with gardening.

Kathaab - sorry for side-trips on your posting /..\

Most seedlings want the soil somewhat moist, but not soggy. It's always better to water from the bottom, which is why seed-trays and pots have those little holes on their bottoms. Watering from the top can really upset the seedling - even if they don't drown or get upset from being doused with cold liquid, top watering has a tendency to encourage nasty stuff like "damping off" which will kill the seedlings. You can help prevent damping off by watering from the bottom and by providing good air movement (the breeze from a fan is fine) - which also helps the babies grow stronger stems. If you are growing directly in the garden, mum-nature provides the breeze; and you provide the finger which is stuck into the soil to check for moisture. If your finger feels damp, don't water.

You didn't tell us the name of the plant, so it's hard to guess why the leaves turn yellow, although drowning will do that.