If liquid organic fertilizers are like tasty, edible, digestible soup for your
plants then top dressing is the porterhouse steak and fries. Plants love
liquid, organic feeds, you know stuff like Bio-Thrive grow and bloom, because modern
formulations like these are bottled in the form that's typically just a step or
two back from full mineralization. That means beneficial biology in the soil can
break it down very easily to become plant-available. So what about top
dressing? Well, slow-release, organic fertilizers can provide a crucial
backbone of nutrients throughout the lifecycle. You take organic powders-- this
is solid inputs, rather than liquids, and sprinkle them onto the top of the pot or
around the base of your plants, then water in. I'm talking about stuff like
bat guano, seabird guano, dried processed sea kelp, bone meal, and alfalfa meal. You
can buy the stuff individually or you can use composite blends that have been
specifically formulated for different times in the plant lifecycle. Of course,
there's more to it than that: like what type of organic stuff should you use, and
when, how much, how often? I'll get into all that, I promise, but let's get started
with the best way to actually top dress your plants. First, some general tips: be
sure to spread your top dressing mix evenly across the top of the soil using
a hand fork, or trowel, to sort of scratch it into the top layer to distribute the
material evenly, and prevent caking when watering through. I like to mix my top
dressing ingredients with compost and then top dress. The houmous contains
microbiology that gets straight to work on breaking down the organic matter.
Next, which inputs to use? If your plants are
still in veg and you notice some of the older leaves are turning pale, this could
be a sign that you need to up your nitrogen levels. Blood meal, chicken
manure, feather meal, and bat guano are your go-to's for a nitrogen boost.
Personally, I prefer to use a blended product such as VermiVeg, as it's been
formulated to deliver high amounts of soluble nitrogen, coupled with a full
micronutrient profile. For a light feed, use half a teaspoon per gallon of soil, or
1 cup per 12 square feet, every other week. For heavier feedings, repeat weekly.
If you're sure that nitrogen is the only element that's lacking, then bat guano is
your best bet. You can buy it separately such as VermiBat, but be careful, as
almost half of the nitrogen it contains is immediately water soluble and so very
fast-acting. The microbes in bat guano are an added treat for your plants, too, and
there are additional benefits such as chitin (insect fragments) that help to
stimulate your plants' immune systems. Try a half a teaspoon per gallon of soil, or
one cup or 12 square feet. Yep, I told you it was strong. For a more timed-release
nitrogen source, say over 6 to 8 weeks, go for blood meal. It releases
fairly rapidly, and is broken down very quickly, especially in media inoculated
with beneficial microbes. Use it just like bat guano. For plants
heading into flowering and fruiting, you should be thinking less about nitrogen
and more about phosphorus. Essential for cell division, and the transport of other
nutrients, which results in huge flowers and fruits. Purplish discoloration of the
leaf margins is the classic, but late sign of phosphorus deficiency. Seabird
guano, and steamed bone meal are your go-to organic soluble phosphorus sources,
especially for short-cycle plants with a 10-week flowering cycle or less. About
half the phosphorous and steamed bone meal is instantly available with the
other half becoming available around 6 weeks later. Calcium phosphate and rock
phosphate are a much slower release-- between 2 and 3 years. They are best used
at planting time, and in beds that are being used for several seasons. However,
once again you can make your life easy using premixed blends. In this case, you
can't really beat something like VermiBloom, as all the individual raw
ingredients have been blended into ideal ratios for optimal uptake. For a light
feeding, use half a teaspoon per gallon of soil, or one cup per 12 square feet,
every other week. For heavier feedings, repeat weekly. Potassium is another key
element associated with the transport of water nutrients and carbohydrates within
plant tissue, and is often required in elevated amounts during the flowering
stage. Along with phosphorous, your fast-growing, heavy-fruiting, annual
plants will almost certainly thank you for a boost in this primary element as
they start to form buds, flowers, and fruits. A simple organic potassium input
would be powdered kelp meal, or a soluble seaweed extract, or a general PK Boost
blend. Many flowering plants can get hungry for both phosphorus and potassium
during mid to late flowering, and the blend insures these crucial elements are
delivered at optimal ratios for uptake. Always water your top dressings well,
ideally with some actively aerated compost tea diluted with 50 parts
dechlorinated water. Repeat applications every two weeks. Compost tea turbo-
charges the breakdown rate of organic inputs, meaning your plants can access
the nutrition sooner. Finally, for outdoor plants, try making a small crater around
the base of the plant to help retain water, and stop your top dressings from
being washed away. If you're already using liquid, organic nutrients, then take
it easy with top dressings. Try halving my application rates and they should work
great together. Okay, I'll stop there. I hope your outdoor plants are starting to make
you feel small! Don't forget that subscribing to my channel is free, and
it's a bit like topdressing for my soul, so click that big red button and send me
some solubilized love! Bye for now, amigos!