1) The most reasonable approach to insect infestations is to tolerate a certain population of pests as long as it doesn't stress the plant too much; then, when populations to grow more numerous than what you have established as reasonable, press the least offensive remedy that will bring populations back into line into service. In your case, you must also consider the fact that that you will be applying the remedy to plants you will consume, so of course o/a safety and safe intervals between application and harvest are important considerations. Neem oil and/or insecticidal soap may be all you need.

2) It does matter for the edibles. It shouldn't contain any elements or compounds that can be absorbed by the plant or that will leave potentially toxic residues on the plant. Also, if you make your own soil, it should not contain anything phytotoxic (poison to plants) or anything that breaks down so quickly its decomposition causes the soil structure to collapse or hold too much water.

3) If you mix your own medium, it should all be mixed together, but I wouldn't be too concerned with sterilization unless you're using it for cuttings or seed starting where damping off diseases are sometimes troublesome. The pathogens that make soil 'unsterile' are usually airborne, and if the soil is hospitable to these organisms it would quickly become infected with them any way. Remember to add appropriate amounts of garden lime when you make your soil (adjusts pH and makes calcium and magnesium available. These elements are not found in most soluble fertilizers). It's best if you wait 2-3 weeks for the lime to adjust the soil pH and get through its reactive stage so it becomes available.

I would encourage you to learn about soils and how to make your own. You can generally build soils far superior to what you find in a bag at less expense.

Al

Lonetraider, you are going to receive a lot of infgrmation about "making soils" from certain quarters that have made many such messages in this journal covering just such requests by you.

I don't go along with making soils, I figure the experts, the ones that sell such products with a name on the bag, know their stuff and can be relied on for what is best for a plant.

Firstly, I am sure you are aware that once you put soil into an oven, the aroma from such is not what a kitchen is usually thought of in the way of its smells.
Before you do it, if you have not experienced it before, do read about its how's, whens, where's......and especially why's.

As far as insecticide, I suggest you read about the particular plant's needs. Some plants react to sprays on its foliage, others, like Cygon 2E, are systemic and can be used to advantage on certain crops---some as early as the day of its harvest.
With Cygon, a pamphlet is part of the purchase which describes the product's use and what plants are safe to use.
With the added caution about testing the product on tips of leaves and waiting until its effects, if any, are noticed within a specified time.

One insecticide you can rely on to kill many bugs and pests is soap and water. Soap...when described used in this manner is just that...S. O. A. P......soap, not detergent.

Soap, is an astringent....i.e. it dries up what it lands on.
Our skin, often when allowed to have excessive soap on it, can feel dry and scratchy. On a bug, it dries out their shells, skin and clogs up their breathing.
But soap is not good for the plant because, it too, clogs up the way the leaf or stem takes in water and air.
So soap solutions used in such sprays are usually in low solution...1%, 2%, 3% is quite effective on bugs.

But, like many insecticides, you should know what you are spraying for. If you can see a bug, then the best method is to pick it off by hand and either, squishing or depositing in a soap/water solution.
If they fly or leap and otherwise avoid your using your fingers, then soap and water, sprayed so that all parts of the plant, making sure to cover the undersides of leaves, can be implemented.
A good solution for most houseplant pests is 40 parts water, one part soap. Sprayed to cover all surfaces, then wait 10 minutes or so, then spraying warmish clear rinse water over the same surfaces, No residue of soap should remain on a plant.

Many bugs begin their lives in the soil of the plant. Bugs usually have very short cycles of lifespan. From egg, to larvae, to adult stage may occur in as little time as 7 days.
So you can see, once you start a program of spraying, continue its effectiveness by spraying every 7 days for at least 3 treatments. Often this will break the cycle of egg to adult and your plant is usually free of this menace.
But, continued vigil is always the by-word.

In the U.S., their spray bottles usually contain a quart...about the same as the Canadian "litre"...so any solution should be made with its percentage of soap in its make-up. 32 oz..(U.S. qt) a 2% solution would be made with the use of 3/4 oz (about 5 tsp) soap, 32 oz. water.

There are many named insecticides on store shelves that bears the names of many pests associated with many named plants. These can be reliable to do what they claim.

Many bugs can be controlled by wrapping the entire plant (and pot) in a plastic greenhouse. By lifting a corner of such envelope, the insecticide is sprayed to make contact with all surfaces...top and bottom, then the envelope is closed and 24 hours later the plant is looked at again. If bugs are still seen, a repeat spray can be considered.
Sometimes tho, what you spray can be as harming as the bug itself....so do read the label of such product and understand its limits.

Many bugs, such as aphids, can be controlled somewhat by simply misting the plant occasionally. The added benefit is providing moisture to the leaves.

lonetraider, one of the above posts is full of rubbish. Hopefully, you can decide which.

Not to confuse you more, we do need to know what kinds of insects you have. Some pests like spider mites need a more potent concoction than say something for aphids.

Most potting soils are for those who don't knw what they are doing soil-wise. As an example, there are some cactus soils which contain moisture polymers, which cause rot very easily. So to say all soils are acceptable for the plant intended is naive at best. Don't be afraid to experiment with your soils.

If you know what you are doing about the soil issue, then hopefully you have confidence in giving your plants what you concoct. Otherwise, do your own research about why potting soils are sterile and why you should stop and think why you would use anything less.

There are always exceptions to the rules and by quoting one does not do you justice when you have concerns about soils.
Hel*, if you want another example, there are plants that don't grow in soil at all....they grow in the air.
Does that suggest you don't need to buy or make soil.

Lonetraider, do your own thing, let what decision you make for your plants be yours....not somebody else's who have ??ideas about what is best for you --according to them.

Loantraider...are your plants buggy? Is that the reason you're seeking insecticides?
If your plants are without bugs, why apply anything? If there is a certain type of insect you're trying to rid, then use something that will kill that particular pest.
Since you're growing edibles, (citrus and lettuce) be very careful what you use. I wouldn't think of adding chemicals to something I'm going to eat.

I mix a home-made, old-fashioned type insecticide, w/basic, home-made ingredients found in most homes.

As a preventative, I spray plants ever 4-5 wks, using 2-4 drops dish soap, (not Dawn) crushed garlic, citrus rind, and recently started adding hot pepper, eg. Cayenne..
This remedy does the job, and nothing will harm you, your family, pets or plants.
It particularly rids mites. It doesn't kill mealy. Then again, considering I have over 300 plants, it's been 4+ years since mealy has attacked a plant. It doesn't prevent or kill scale either, but if scale is found on a plant, I add Fish Emulsion with the other ingredients. FE kills on contact..BTW, in autumn, when my plants are brought in, they're all sprayed with the home-made mix and Fish Emulsion..The FE is used to prevent scale. I was told this trick by a woman in Fl who owns a citrus nursery..Two other reasons I prefer Fish Emulsion is it's organic, and used as a last foliar feed..Since it's organic, it will not burn roots or leaves. There are other oils, like Neem, too. Good luck, Toni

i just noticed a green fly that's all, i'll post more when i can (mobile phone internet :) ) i'll have to read in full all of your helpful posts as well!!

I assume you mean aphids, since the only "green fly" we have in the states that I know of is a green bottle fly related to a house fly. I had to Google "green fly" and "UK". One aphid could just be squished with your fingers. Keep an eye on the plants for a while for hatchlings and eggs. You can control aphids with a brisk spray of water all over the plant, being careful to get the undersides. Soapy water would kill the rest of them. I would dare to say you aren't needing an insecticide just yet. I would keep the lettuce away from the other plants, just in case, since aphids love lettuce. None of those listed are the type of plant that aphids would like all too much except the lettuce. Keep an eye on the lettuce, since it will be the problem, the others may have one or two, but not many. If you keep squishing and swishing, you shouldn't have to get any insecticide at all.

i've separated the lettuce from other plants & am going to make my own insecticide with garlic (and apparently basil leaves are effective against aphids as well!!) but only if i spot anymore infestation. I think I'll make my own compost with perlite, coir and lime. I mist all of my plants twice a day anyway so hopefully that will help.

i have another question, when re potting would it be wise to add a layer of moss to the bottom of the pot to prevent compost exiting via the hole? i don't want to use broken terracotta pots as i only have unbroken terracotta pots!! I've always felt that it was a bad idea anyway as broken terracotta can be quite sharp, and roots would be better away from sharp objects i think.

No, no, no.

Pls. do NOT use any layer of moss or anything else, nor broken pot shards, to keep the mix in. These can interfere w/ proper drainage.

All I use are a couple of layers of newpaper (I trace around the bottom of the pot & cut it out), which I place in the bottom of the pot before I add mix. You could also use paper towels or coffee filters (expensive) for the same thing. Yes, they'll disingtegrate over time, yet I never have trouble w/ mix leaking out, tho' I DO use saucers under all my plants.

I wouldn't mist twice a day, think it might be too much especially for the Ficus & might lead to rot.

If you're a newbie perhaps avoid the lime -- if you don't know what you're doing you could muck up the PH to the detriment of the plants.

Often simpler is best, especially for a newbie.

(IMO = In my opinion) You'd be better served browsing some basic houseplant books, like at the Library or your local bookstore to learn the basics BEFORE you do some of this other stuff.

Good luck w/ them!

Just a passing comment: If you DO make your own soil, you will need a source of calcium and magnesium, 2 elements you find very infrequently in common soluble fertilizers like Miracle-Gro, Peter's, Schultz, etc. That is why I suggested dolomitic lime (virtually all bagged soils contain dolomite for the reason I noted, AND to raise the low pH of peat and bark to a more favorable level). The problem with coir, is that the pH is already high, so adding lime can be problematic; and, it CAN be very high in other salts.

I could explain how to use gypsum instead of dolomite to keep soil pH down, but I think you're still a little new at this, so I won't confuse you. If you're truly interested in learning how to make your own soils and how different ingredients function in soils - what they bring to the table, so to speak, I would suggest you give the link just below a readover.

The soil is the foundation of every container planting (that uses soil) and you only frustrate yourself by attempting to build on a poor foundation - an inadequate soil; however, if you intend to try to give yourself an advantage by making your own soils, you really need to understand what you're doing, or you'll more likely increase the probability of frustration.

Good luck. ;o)

Al

Here is a link that might be useful: About Container Soils

thanks for the link, time to study up!!

Just a little note, I use a couple of coffee filters in the bottom of my pots. Newspaper does last longer, but coffee filters do not have inks, and coffee filters are cheap and on hand. Moss would be a good way to get fungus gnats also.

Garlic can burn the letuce, but what you could do is plant a few cloves around the lettuce, this will help with all sorts of insects.

If you do deside to make your own soil mix, please keep with basic ingredients and not too elaborate until you know what you are doing. Perlite and pumice are your friends and help keep a lot of bagged soil more acceptable. When I first started mixing soils, I started with a bagged soil and added perlite to lighten it up, now I'm up to a few more ingredients added to a bagged soil depending upon what I'm potting.

Fiberglass window screen is what I use in my pot bottoms. You can cut it to any size/shape and it lasts forever.

That's what I use in most containers. In bonsai pots, I use plastic canvas - as you would use for needlepoint. It comes in very inexpensive 9 x 12 sheets (hobby shops) & the square holes are approximately twice the size of those in insect screen. It lasts indefinitely.

Al