I usually do a foliar feed once a week, but it's not my sole method of fertilizing. I know it's controversial, but what the heck, it's not doing any harm. I used to foliar feed my tomatoes when I grew them and my tomato yield was much greater with it than without. Whether or not that translates to orchids or was actually due to foliar feeding is beyond my knowledge, but I do it anyways. I alternate between Dyna-Gro Grow and Age Old Grow which includes fish emulsion and kelp but is odorless.

Natural equivalent? Rain water wets entire plants not just roots. Rainwater is mysteriously more effective than normal fertilization. Rainwater is usually ionized through lightning. You are thinking in terms of liquids. Leaves have evolved to be able to extract oxygen, nitrogen and C02 from air directly. Water was its first domain and most of the plants still have the ability to do so. Green algae have no roots. Aquatic plants or halophytes have roots but nutrients in the form of ionic solutions donÂt need to reach the roots to be absorbed. In aquatic plant keeping you will learn that you don't need to circulate your water (that has nutrients added) through the substrate, even if the substrate has no nutrient base at all. The plants sucks nutrients out of the water equally as fast, there is no difference. Some halophytes you find in aquatic plant keeping you wonÂt find growing in water when you go look for them in the wild. The only differences between a halophyte and a non halophyte plant is that their skins are adapted not to dry above water or to be able to access dissolved gasses below water. The one adaptation messes up the other ability. So in my opinion, plant foliar feeding will vary between plant species. Tough waxy plants will be less effective while soft fast growing, higher humidity or "higher plants" will be more effective at utilizing foliar feeds. Controlled studies exists but is probably so old you won't find them on the net. It's common knowledge in my opinion. Maybe someone should post some fresh studies.

I talked to a supplier and was told that the liquid will mold over time and keeping it cool will help slow this down. I live in a hot climate and buy the powder so I just mix what I will use. This also lowers the shipping cost. The powder must be kept dry or it will turn to paste which is still usable, but messy. I'll repack the powder into smaller airtight container to try and keep it dry. I was given a gal, not sure what brand, of the liquid as a gift and used it for several years with no noticable mold problems, but it did thicken up. Think it is really a matter of availabitity, cost, and personal preference. Kelp is sold as a meal or as an extract of the meal in liquid or powder form and provides some 60 trace elements and growth promoting hormones and enzymes. The meal is a slow release and the sprays and drenches are more quickly absorbed. I like to have both methods available. Hope that helps.

That's a two edged question. You don't want to do anything to stimulate new, soft, sappy growth until the chance for your last frost is probably past. Why waste the effort and money only to have the plants frost damaged due to growth much more susceptible to damage than harder wood? Then, organic fertilizers require 'digestion' by soil bacteria and fungi to release their nutrients to the plants. Most of these are dormant in cold soil so the prime benefits of your expensive food is often wasted. You would be far better off (as will your roses) to wait until the air temperatures begin to warm closer to the seventy degree mark, so the soil can begin to warm and stimulate the bacteria to begin "eating" the organics. Remember that colder night temps cool the soil back down, slowing the bacterial action and reducing the benefits of the fertilizers. If your plants are potted, they'll begin to be able to use the fertilizers earlier because sun shining directly on the pots heat them up faster, earlier, so there is more digestion going on while they're heated up, but they also cool off faster as that absorbed heat radiates back out into the colder night air. The actual date is going to vary greatly by your micro climate, but you can figure that out based on your air temps and when you think it's safe to trigger the soft new growth without subjecting it to certain freezes.