Re: The Best Natural Repellent

HI..
There are many, many herbs that have been used for insect repellents, to 
name a few: 

bay laurel	basil    	cedarwood
chamomile	clover flowers	feverfew
garlic	        ginger	        lavender
mint	        onions   	pennyroyal
rue	        sassafras	savory
southernwood	vetiver	        wormwood

These above are normally considered to be the most commonly used.  From 
your list ginger, garlic, onion, lemon grass, clove, pandan leave, chilli 
and cinnamon; I have also seen lemon grass, and clove used though the 
clove seems to be used more to mask the odors of other ingredients rather 
than a repellant by itself.  To list their effectiveness in order as 
general repellants is pretty hard since the results would vary upon method 
and area of application, type of insects,  and  other variables.  An 
example is that basil seems to work well on flies and pennyroyal on 
mosquitoes but the reverse is not true.  Economics also becomes a 
factor.  It would considered to be rather expensive to scatter ginger or 
any large area as a repellant.  
    As far as cockroaches are concerned the most natural way of repelling 
them is to first make sure that there is not a suitable environment for 
them to inhabit.  Store food products in sealed containers, make sure to 
keep trash , debris and garbage to a minimum around dwellings.  Boric 
acid, placed around the base of walls  works very well to eliminate 
roaches and is relatively safe though not a natural repellant. 
  There are a lot of websites devoted to herbal gardening and natural 
product utilization.  You may want to search some of these sites since 
they often list home brews and herbal concoctions that people have used 
and found useful as repellants. 
    Finally,  I don’t know about insects, but my wife’s chilli usually 
creates a gas that repels humans quite effectively about 2-3 hours after 
you eat it. …..   Mark