Sand is good in small amounts with a soil mix and desert sands CAN be good, as their calcium-rich alkalinity can sweeten carrot flavor, but if those sands are too salty, most vegetables don't like soils with too much free sodium. Rinsed sands are one way to avoid this, you can wash out some sodium chlorides & carbonates while keeping the calcium & manganese oxides. I have to admit I have no idea about the particulars of Dubai desert sand and am generalizing based on California's desert sands. Sounds like what you need is fully composted organic matter - grass, leaves, bark, manure, ... Sand has essentially no nitrogen and purchased soil often lacks the useful microrganisms that help process dead vegetation into usable nutrients anyway. Some mall soils are mainly useful as a way of maintaining drainage in containers and preventing root rot, but if they are all you use, it's like putting your crops on a diet. That's why so many people add chemical fertilizers to container plants. But you want to try and avoid bringing in diseases or pests along with the compost, there's always some risk with non-sterile soil amendments. It's a bit of a balancing act as well as the subject of quite a lot of discussion about creating perfect soil mixes for particular plants. As a novice, you mainly want to understand that you must have nitrogen to even get the plants growing, then phosphorus and potassium (N/P/K on fertilizer labels) and micro-nutrients for crop production. Desert sands will almost guarantee you potassium and if you want to extend your gardening knowledge into ecological knowledge about your surroundings, using various native soils in your yard can be very educational.

oppalm: I don't know what you mean by'Is this a great country or what'? What I am saying is a fact. You can go to Walllmart and buy a citrus trees grafted for $9.00 ones that are in pots 4x4x18. They are one year old tree. I can bet that in 2 years time you should have flowers in them. If you want bigger trees go to Home Depot or even Wallmart or Costco or Orchard you can buy citrus trees that have if you are lucky have fruits already in them. My favorite place to go is Home Depot in that most of their ctrus are dwarf and have fruits in them. All you need is wait about 8 months and you can taste the fruit of your labor. Usually the costs are from $19 to $24. Are you insinuating that that is too much? I would like to know how much citrus trees cost in Russia or in Europe if you can find them. I think that price is reasonable considering the expenses they spend from their nursery to the consumer. I am not good in telling you that if you plant a citrus seed and possibly you will not get the same fruit as the mother plant. All I know is what I read in here. I read that the fruit usually are inferior in taste as that of the mother plant. Whereas a grafted tree which you bought from the store are the same plant as the mother plant. They are identical. The citrus plant has nothing to do with USA or country.

The large ones take some care. If you trellis them you have to provide them with support, and if you run them on the ground they have to have lots of room. There's nothing more heartbreaking than to walk under your trellis on a nice morning and see that your biggest gourds have hit the ground and broken (sigh... yes... imagine over a dozen broken ones in one night, I didn't think they were heavy enough yet to fall, lesson learned). Anything that will support them is good, some folks use old pantyhose (which is great and doesn't leave marks, just slip the gourd inside and tie it up to something strong. One way or another, you have to protect them from falling.

I really do not think that turnip(s)should be grown in a soda can. A soda can is probably to small. Since you are doing recycled planters, you could try a watering can. Of course, the watering can is not meant for turnips, but I just think that watering cans are by far the coolest recycled planters out there. I used one last year, and it worked out pretty well for me, so everyone who is reading this, please give it a go!