a good soil rich in humus ...

they are plants.. they do NOT need to be fed ...

but they do need a good soil ...

add compost to your beds in fall.. and then they wont need 'food' next year ...

ken

That's right.

Way too many people have been brainwashed about the made-up need for constant fertilizer thanks in part to the wonderful ads fertilizer companies bombard us with.

If you listen to them, the secret to growing everything is in the fertilizer. Nope. The secret is providing the plants with the basics they need: proper soil, proper levels of moisture, the right temps and the right light. Fertilizer is just s little added treat for the plants.

Kevin

I don't like to pile on, but somehow all the hype about synthetic fertilizer needs to be exposed, for its real reason, which is to make money. A healthy soil with plenty of microbial life is all your plants need other than water. Al

I agree to some degree with the above statements -- namely, that many gardeners mistakenly believe they need to fertilize often to grow healthy, vibrant plants. This certainly isn't the case with most perennials (daylilies, phlox, hibiscus are exceptions), though annuals probably could use regular feedings during the growing season because they consume a ton of nutrients to produce many flowers over an extended period.

Like humans, all plants require nutrients (or "food" as we call it) to grow. Often, the soil already contains plenty of nutrients so supplementation is not necessary. Most perennials in most soils will do fine with a yearly top-dress of quality compost.

However, it is foolhardy to assume we know the original poster's soil type and nutrient content without being provided that information. If he or she has very sandy soil, for example, nutrients could very well be lacking. In these situations, supplemental fertilizer can play a key role in maintaining the vigor of plants. Ideally, you would test your soil for micro- or macro-nutrient deficiencies before adding anything. Not doing so is really like shooting in the dark. If you are going to shoot in the dark, it is best to do so with something that is either organic (e.g. compost) or slow-release (e.g. Osmocote) to keep from overloading the plants with nutrients and potentially damaging them.

As for your specific plants: Astilbe are heavy feeders as far as perennials go. However, they really only need some compost or perhaps some slow-release granular fertilizer like Osmocote worked into the soil in Spring and they will be fine for the rest of the season. Phlox are also heavy feeders (even moreso than Astilbe). Like annuals, phlox tend to use a decent amount of nutrients for their extended bloom period. So, some supplemental slow-release fertilizer like Osmocote would be nice in Spring or Miracle-Gro (gasp!) monthly or every other month during the growing season. (Always follow package directions and do not use more than specified!)

The above all assumes "perfect" loam soil (which really does not exist except maybe in raised beds). Clay soil tends to retain more nutrients and sandy soil tends to lose more nutrients than loam. You will probably want to tailor your supplemental fertilizer applications to your soil composition.

I hope this long-winded diatribe helps!

I still stick by my original statement the role of fertilizer is overstated and too many people find excuses for using it.

A couple of examples:

Every garden plant has a "wild" counterpoint. Who is fertilizing those plants? Seems to me they do quite well on their own.

I'm an orchid grower. If you've ever participated in some of the orchid forums, the question of fertilizer is always being raised. When most newbies post their questions about why their orchid is dying, they often state how much they've been fertilizing it and it's still dying. When more questions are asked about under what conditions they're growing it, we always find out that's the problem: not enough light, too much light, wrong temps, wrong watering etc. Yet, way too many people think fertilizer is the answer to every aspect of a plants overall health.

Have you ever seen a photo of a orchid growing in the wild? The vast majority of them grow on tree branches, tree trunks, etc. And NO, they are not parasites, orchids are epiphytes. They simply use the tree for support, They take nothing from their host.

Again, who's fertilizing these plants? They exist on whatever bit of fertilizer happens to come their way. Maybe a little bird poop washing over their roots or some decayed leaves doing the same. Their diet is lean by any-ones standards and yet they thrive. In fact some of these plants can get so huge, they break the branches that are supporting them.

I also raise questions about this plants labeled as "heavy feeders". Who determined that? What exactly do they mean? I've never fertilized my astilbe or phlox. The phlox would have been wonderful this year had not the squirrels chewed them down a couple of weeks ago. The astilbe were magnificent this year, not because of fertilizer, but because of all the rain we had.

I was at my parents a couple of weeks ago. For health reasons neither of them have been able to tend their garden in many years. There was a phlox in full bloom, easily 3 feet across with huge flower heads on every stem. I doubt that plant has ever seen a drop of fertilizer it's entire life.

Kevin

Kevin, I agree with your statement that fertilizer is an over-emphasized aspect of gardening and other factors such as water, light, drainage, etc. are more important than supplemental nutrients. Like I wrote in my last post, for the vast majority of perennials, a little compost here and there is all that is necessary to keep the soil nutrient level high enough for most perennials.

A "heavy feeder" is just a plant that tends to consume nutrients (namely, the macro-nutrients nitrogen, phosphorus, and potassium) at a greater clip than others, most likely because they bloom prolifically for an extended period. In these situations, there is a *possibility* that the plant will use soil nutrients faster than nature can replace them. This usually isn't the case, but it can happen, especially with sandy soils. In these cases, limited supplemental fertilization can improve plant performance. Sure, many of these plants are natives and do just fine in wild conditions -- but we can optimize their performance in our gardens (maximize bloom quality and duration) if we make sure they have an ideal nutrient balance.

My philosophy is always not to mess with something unless there is a problem. If your plants look great each year without supplemental fertilizer, then by all means, leave them be and save yourself unnecessary work.

Shelley - Do you have a particular concern about the health of your plants? If so, posting a photo may get you some specific advice. You can also get a soil test done to see if your soil is missing some particular nutrients.

I am another person who doesn't feed either phlox or astilbe (or any other plants except occasionally potted annuals) and they seem pretty healthy and happy. I do add a lot of compost to a bed when it's first created since in my last couple of gardens there's not been much organic matter in my soil. I top dress with organic matter of some kind every couple of years for moisture retention, weed suppression and to add nutrients slowly over time. This has seemed to work well regardless of soil type over the years in several gardens, though I haven't gardened in coarse sandy soil like on Cape Cod.

I think for me the biggest argument against most quick-release fertilizers for either lawn or garden is that because it is highly soluable and the plants can't use it as quickly as it becomes available, much of it ends up in water, either ground or surface water, and contributes to algal blooms and water quality issues.

Actually, my astilbes are basically healthy. My phlox could
use a little more sun (they only get 4 -5 hours) but the flowers are pretty full. I had read that phlox and astilbes are big feeders. So I'll put some osmocote under them in the spring and see if they bloom fuller. My soil has been tested and it's very good. Thanks for all your responses.

so after all this debate.. she is just going to throw a handful of fertilizer under them..

and not just the cheap generic stuff.. but the most expensive time release type ..

ma'am ... you are a marketers dream ... if they tell you next.. they need to be tucked in for winter.. will you start looking for garden blankets.. in late fall .???? .. perhaps education??? ...

but trust me.. in july/august.. NOTHING you throw under the plant.. is going to increase bloom .. there simply is not time for the plant to synthesize product.. in a useful manner ... before bloom fades. .. ergo.. you are doing something not necessary.. and some of us might suggest that is pollution ...

plus .... you freely admit.. that this FULL SUN plant.. is in too much shade.. and the number one problem with a large flowering plants not performing to expectation.. is lack of FULL SUN ...

i will repeat.. and you confirm with your soil analysis.. that nothing is lacking in your soil.. why are you adding to your soil then????

i apologize if this sounds angry.. its not meant to.. i am just frustrated by your logic.. you know the problem.. lack of full sun.. and you are hoping some chemical intervention [fert] .. is going to change the genetic disposition of a plant that needs full sun ...

my phlox are in mineral sand .. never get water .. and are in full blistering sun all day long.. they have HUGE flower heads.. and otherwise.. look like carp.. lol ... but surely.. fertilizer will not help them ... a good soil would .. but who cares.. all i want is one week of that heavenly scent..

good luck .. and have fun...

ken

The OP was asking for advice about which fertilizer to use for her specific plants, not to be lambasted about how fertilizer is an incarnation of the devil and how dare she even think of using such a vile thing. Some people want to fertilize; let them do it. It is their garden, not yours.

She said she would fertilize in Spring, not now Ken. Osmocote is eco-friendly and actually it is cheap -- you only use about a tablespoon (or two) per plant per growing season. I have been using the same bag for several years and I am not even halfway through it. It is basically cheap insurance against any future nutrient deficiencies. Calm down!

But, Ken, you are right that fertilizer absolutely will not compensate for a lack of full sunlight. Lack of sufficient light will probably impact bloom quality much moreso than a small deficiency in a micro/macro nutrient.

Several week ago there was a question about favorite garden books and from that I ordered The Well Tempered Garden. It has proved to be a delightful and helpful book. On page 24, Christopher Lloyd writes "It seems a pity, though, when crankiness is carried to the pitch of eschewing all artifical fertilizers; for an adequate all-organic manusrial programme in the garden will generally run you to considerable extra expens. The use of artificials by themselves over a period of years is harmful in the negative sense; you are failing to replace the continuous losses of organic matter from the soil that are inevitable on cultivated land. But if their use is combined with applications of bulky organics such as farmyard manure, garden-made compost or peat (whose nutritive value is nil), artificials are excellent.

^ That speaks directly to the idea of replacing nutrients lost over time. Wild plants typically exist in an ecosystem (prairie, woodland, etc.) where there are natural processes that replenish soil nutrients. For example, in the Sandhills of North Carolina, wildfires help return nutrients to the sandy, infertile soil.

In other cases, wild plants (such as orchids) adapt to reproducing with fewer available nutrients than other plants or by using unique methods (such as fungi symbiosis with orchids) to obtain them. Plants with these types of adaptations include many of the wildflowers we grow in our gardens (Echinacea, Coreopsis, etc.).

In our rural, suburban, and urban gardens, ecological processes (such as leaf decomposition) that replenish nutrients do not always happen or they happen to a much lesser degree, leaving open the possibility that the soil will lose nutrients over time. That is why there is a role for fertilizers (including compost) in maintaining plants native to fertile woodlands like astilbe and phlox.

It is a better endeavor (in my opinion) to try to build a quality, humus-rich soil horizon instead of just adding N-P-K fertilizer (which is really just a band-aid) because quality soil (which you can build over time) has many benefits in addition to supplying plants with nutrients -- it helps retains moisture, prevents plant disease, encourages development of beneficial soil microbes that aerate it, and is able to retain plant nutrients better (chelation) than humus-deficient soils. It also makes those nutrients less likely to leach into the watersheds.

I tend to agree with most of the comments above. However, there are always extremes. I live on top of a gyp hill. For 45 years I have added to the soil and its never ending. Humus is gobbled up, and just disappears every year. I use leaf mold, my own compost, manure, alfalfa pellets(wonderful stuff) and at least 10 bags of mushroom compost a year. I also fertilize when I think something else is needed. The world won't come to an end if she does. some plants could possibly use something extra to thrive. We as gardeners know that certain plants do better in our conditions than others, so if we want to grow things that don't do as well in our conditions, what harm in giving them the little something extra to make them thrive. I seem to be repeating myself, so better quit. remember in gardening there are always exceptions to the rules. I may have been at this for many years longer than any of you, but I can always learn something from most any gardener if I just listen.

I agree with most of the above comments except that I consider mulch and compost to be fertilizer. Perhaps we should distinguish instead between commercial chemical fertilizer and organic material. Both add nutrients to the soil, but the latter lasts longer, adds bulk to the soil, and is more environmentally friendly.

My phlox grow on a slightly sloping hillside with good drainage, in soil enriched by centuries of cow and horse manure from its previous use as pasture, to which I add aged manure every couple years in the fall and nothing else. My phlox plants are at least 10 years old and this is how they look under this care regimen.

{{gwi:255130}}

I agree that compost acts as a fertilizer because it contains nutrients, but it may be restrictive to only think of it as fertilizer when it has many other benefits. However, I dislike the use of the word "chemical" when describing synthetic fertilizer because every fertilizer including compost contains chemicals (e.g. nitrogen, phosphorus, and potassium). I don't understand why opponents of synthetic fertilizers often use the word "chemical" as a pejorative adjective when the oxygen that sustains our existence is in fact a chemical.

Anyway, I think the ideal is to use something that improves the soil (such as compost), but I also do not think there is anything wrong with adding some slow-release synthetic fertilizer as nutrient insurance to your soil, especially if it is sandy, rocky, urban/suburban, or otherwise poor at retaining or replenishing nutrients.

I like the word "chemical" when describing synthetic fertilizer because it tells me a little bit about how and where where the fertilizer was produced. I want to know what I'm putting on my garden. I also want to know whether the manufacturing processes involved are harmful to the environment. In other words, I want as much information as possible as quickly as possible.
I understand the plant can't tell where the chemicals it is receiving are from, but i can, and that is one of the choices I get to make and will continue to make as a gardener.
I know that by purchasing chemical fertilizer, I am supporting the petroleum industries and the war industries (after all, that's where chemical fertilizers came from- remnants of petroleum based poison gases used to kill people).
Oxygen is not a chemical, but an element.
Ken's answer was, as usual, succinct and sensible. He went to a certain amount of trouble to answer the poster who didn't bother to thank him, but insisted on ignoring entirely what he wrote. He knows whereof he speaks.

Of course anyone has the right to use whatever terminology they prefer but mistascott is correct - ALL fertilizers, organic or not, synthetically fabricated or not, are chemical-based. We might want to check our definitions, but anything listed on the periodic table is a chemical element and the standard definition of 'chemical' is "of or relating to chemistry or of or relating to the properties or actions of chemicals." There is nothing in this definition that limits this to synthetically derived fertilizers.

Heck, since humans are carbon life forms (and carbon is a chemical element), not to mention containing some 60 other chemical elements, we are pretty much walking chemical compounds! To disparage this terminology or to unnecessarily restrict it to synthesized or manufactured materials is to ignore an entire aspect of our scientific make-up, namely organic chemistry.

And I really object to calling fertilizers plant food! It tends to anthropomorphize plants and gardening, which is totally inappropriate (hear, hear, Ken!) as well as misleads one about the actual botanical processes involved with how plants grow. Plants make their own food - it is called autotrophism and is the purpose behind photosynthesis. All fertilizers do is provide access to nutrients that may be deficient or missing in the soil. Outside of container gardening, they are never a requirement and as noted, with a good organic mulch, can often be eliminated from use altogether.

Aside from this semantic clarification, I tend to agree with the majority of the posters. We tend to get brainwashed by the big fert manufacturers into believing we cannot garden successfuly without frequent applications of their latest and greatest. That is simply not so. Most plants established in the landscape are able to draw all the nutrients they need for healthy growth from the soil. There can be limits however and this where the advantage of soil testing comes into play. But generally, replenishing your soil with organic matter via mulch/compost is all the "fertilizer" you will ever need.

ninamarie, a chemical is defined as "a substance with a distinct molecular composition that is produced by or used in a chemical process." Oxygen has a distinct molecular composition and it is produced by or used in chemical processes. It is a chemical element. The word "chemical" in this context is an adjective meaning it describes the type of element. Therefore, oxygen is indeed a chemical. It is a specific type of chemical -- the simplest type -- a chemical element. A chemical compound (perhaps what you think of as a chemical) is formed when atoms of more than one chemical element combine.