I'm not quite in your zone but I do have to watch out for higher temps and, especially, wild fluctuations. So I'll take a stab at some advice.

It can be hard to keep containers watered once you open them up (after true leaves form and the plants begin to really grow). For that reason I think it is EXTRA important to make sure your containers are deep enough and hold sufficient "soil". It will be almost impossible to keep shallow containers from drying out as temperatures go up. Also, it helps to keep your containers in a shadier location. They will turn into vegetable steamers in direct southern sun. I like 2 and 3 liter bottles because they are deep. The more "dirt" the longer it takes to dry out.

For timing about when to plant out... Do you have frost in zone 9? If so, keep track of the normal "date of last frost". A lot of varieties can take some frost but others (tender annuals) can't. Hold off on any that you are not pretty sure can take the cold.

I have had little success with direct sowing, probably because it is so hard to keep the soil evenly moist for germination. THAT is the main problem that wintersowing solves for me. And small children aren't the only predators who can attack your garden. Birds eat seeds. Rain washes them into places you hadn't planned to plant. Rabbits and other varmints eat baby plants. It is really nice to give the little ones a chance to grow a bit before exposing them to the big world.

As for your poor soil...me too. Mine is almost pure sand. I would strongly advise you to take some time to amend your beds before the plants go in. While your little sprouts are growing, work in compost, chopped fall leaves, whatever organic stuff you can find and afford to add to your flowerbeds. It would probably be best to get your soil analyzed. Your county extension office can do this for very little money. That will tell you specifically what your garden lacks and you will probably save the cost in avoiding unnecessary fertilizers, etc. It will NEVER be easier to improve your soil than BEFORE you plant. And decent soil will make a lot of the difference between success and failure.

You have a lot of good questions, but I'm only going to address your question about the suitability ofstrawberry containers. I personally handled 28,000 of them last spring as a part of my Extreme Lasagna Makeover. Consequently, regarding suitability, I can say with some authority: It depends. Not all strawberry containers are the same.

I found myself dividing them into three categories. The first was unsuitable because they became mis-shapen from only a few days in the sun. It looked like they had melted, but it wasn't hot so I suspected UV breakdown.

The second did not break down, but they weren't very deep. I took those to the recycle bin as well.

The third I found to be suitable with some limitations. They weren't really strong enough to hold up to the weight of snow, which is probably not a concern for you. I used them primarily for spring sowing, and taped over a lot of the holes so they wouldn't dry out. The sun did not break them down and they were deep enough. Eventually, I decided they were best suited for storing craft supplies. However, if I needed them in a pinch I would say they were best suited for warm weather, quick sprouters like sunflowers and cucumbers.

I'm not going to discourage you from trying them, but the trend for surefire, reliable containers seems to be for milk jugs, soda bottles and aluminum lasagna pans.

Good luck!
Seedmama

Wow, guys, thanks for the excellent info! I'm a bit bummed all my strawberry containers I've been saving are probably not the best choice and will likely not work. :( Maybe I'll only do limited WSing this year as I haven't saved much else and I'm on a very limited budget. I can probably scronge up a few milk jugs, but not too many.

lindakimy, I forgot to mention that I live in the bay area and we very rarely get freezes here. I have been working a little on my soil, but mostly around existing plants, but you are right, I should work on new beds too. I do get used grinds from cafes, brown leaves, and of course my own compost. Working on the soil is such a boring and tedious job though, not nearly as much fun as working on things growing and planting things! But alas, you are right, necessary.

I might lean towards doing some more spring and summer sowing this year, in containers and such, before transplanting to ground, and see what works with some limited WSing for next year.

Thanks again!

My husband and I consume very little milk. I collect jugs from friends and co-workers. I also get some, though few, from recycle bins on garbage day. Usually they are too scrunched up to be usuable when I find them there.

Karen

Hi, this is my third year winter sowing (I have not started yet!!) And I have learned a few things about sowing in a hot climate. Here I am a zone 8 technically, just because we get slightly cooler in the winter. But we get hot like the neighboring zip codes that are zone 9. Our springs are very short and begin in mid Feb and then by late April or early may we are up into the upper 80s and low 90s. But I can say that winter sowing works great!
Here are some things that I have learned, pertaining to a hot climate any way.

1. concerning you strawberry containers. They work great until germination, then the lids need to be removed right away so the plants don't bend and so adequate water gets in. For some reason the small holes don't let in enough water when watering from overhead.
2. My current favorite containers are milk jugs. And you can water these by just sticking the sprayer nozzle in the top.
3. When it gets hot, plant them out asap or move them to dappled shade.
4. Devise a way to bottom water. if I can have my jugs sitting in an inch or so of water on a very hot day, then I don't have to come out twice to water. If the water isn't used up you can dump it and let them drain, but truthfully I have never had a plant die from soggy roots by doing it this way. Of course you should watch for any of those drought tolerant plants that really may not like this treatment!
5. Plant out early. Yes things will start growing right away, especially those frost hardy plants. Just get them planted out, unless they are especially tender.
OK, I think that is it. I am looking forward to beginning soon, although I won't do as much this year since I will be having a baby in not too long!
eyeballs

Bottom watering is a GREAT idea! Wouldn't have thought of that, I love this place. ;)

eyeballs, congrats on the new baby! Good luck!

One of the best things I found at a yard sale last year was a really large (2'x 3'?) solid plastic, shallow (4"?) bin. I don't know what it was orginial used for, nor did the seller, but it was dirty and had clearly bummed around outside for awhile and she sold it to me for a buck. I was able to fit a whole bunch of milk jugs in it to bottom water all at once during those "dog hot" days we sometimes get. I encourage everyone who is getting into WS to become a yard sale/ thrift store shopper. You will "see" uses for other peoples junk! I am also a big fan of discarded roasting pans and rimmed cookie sheets if they are made out of aluminium that doesn't rust outside. Great for carrying "HOS" to the garden to plant.

Nancy

I also have a similar tub for bottom watering. I bought it for bathing my dog, but eventually not much of that 105 lb. dog fit into the bathtub. But it is great for bottom watering milk jugs. I find this works best in spring when it gets really hot.

Some folks also use kiddie swimming pools.

Karen

I know a lot of people sow in large zip lock bags. And I also used large Styrofoam cups in rubber maid containers covered with plastic or the XXL zip lock bags. Just a thought many things you can WS in. :)
Monica

Last year I picked up milk/water jugs and other containers from recycling bins in our neighborhood. My favorites were the gal. water jugs. They are like milk jugs but don't need rinsing out or have that sour milk smell. Also filling the crushed jugs with hot water helps them pop back into shape.

Neighbors and friends kept jugs for me also but since I sowed 500 jugs I really needed those from the recycling bins. One lady asked why I wanted the jugs. "Gardening project." I replied. She waved and said help yourself.

For those that I cut out windows and used the plastic bag to cover the jugs I reached in the window to take HOS out so was able to save those jugs which I will use again this year.

Plastic ice cream buckets and 2L soda bottles work well, also. Some people use the 20/24 oz soda bottles. Also found some large plastic containers that had holes in the bottoms so they were thrown out. They were good to help coral all those smaller soda bottles.

I tried the strawberry containers my first year and found it difficult to keep the mix moist so did not have good germination.

I used quart zip lock bags my first year. They work well but are floppy and need to be propped up. I poked bamboo skewers through them to keep them from collapsing. Later used clothespins to keep tops open as the sprouts grew.

If you use the search feature for "containers", "Wintersowing containers" you will see some of the other containers that people have used.

Bet you will find that you have or can find some containers to start this winter yet. Good luck.

Bobbie