Fertilizer may be needed and beneficial, but you should avoid the tendency to over-fertilize. Too much fertilizer can be more harmful than too little. Too much can hinder bloom count or even kill the plant.

Ideally, no fertilizer should be added before a soil test can confirm what elements might be lacking, and what elements might already exist in excessive levels. Heavy fertilizing can often result in a build up of excess phosphorus. Soil testing can be obtained through a university extension service or commercial labs. Common home testing kits may not be a good value.

Many hobbyists recommend a balanced fertilizer, with all three main ingredients, something akin to 20-20-20 or 20-10-10. These numbers refer to the three most common trace elements that all plants need: nitrogen, phosphorus, and potash. The formula is NITROGEN-PHOSPHORUS-POTASH, in that order, and is sometimes called N-P-K, using chemical abbreviations.

Thus, a 20-10-10 fertilizer contains 20% nitrogen, 10% phosphorus, and 10% potash. The only difference between a 20-20-20 and a 10-10-10 is that the 20-20-20 is twice as concentrated. Thus, you would need two times as much of the 10-10-10 to equal the 20-20-20. Therefore, the higher the numbers, the more expensive the fertilizer, per unit, and the less of it you need to treat a given area.

The main point is that when someone recommends 20-10-10 and you can find only a 10-5-5 fertilizer, other than perhaps price, there may be no difference. You simply need less of one than the other.

A respected horticulturist told me that daylilies are heavy nitrogen feeders, and he warned, too, against phosphorus buildup. Thus, he advised against balanced fertilizers and was promoting the use of a formula such as 20-5-5, 20-3-10, or even no phosphorus at all. In 1996, following five years without professional soil testing, I discovered that in every bed tested, I had too much phosphorous (the "middle" number), ranging up to 182 lbs./acre-with 100 lbs./acre considered as the threshold between 'adequate' and 'high'. This probably resulted from too many years of indiscriminate use of balanced fertilizers.

Having said that, some experts recommend that once scapes start forming, you should change from a high-nitrogen fertilizer to a lower-nitrogen fertilizer, in order to promote bud growth.

Be aware that so-called "complete" products that contains N-P-K may not really be complete. Plants need small amounts of many elements other than just N-P-K. Three of the most needed other elements are calcium, magnesium, and sulfur. The good news is that these are easy to obtain and hard to over-apply. I do not want to say that you cannot overdo them, but an agricultural lab told me they have never seen it. You can get calcium and sulfur by applying some gypsum to your flower beds, and magnesium and sulfur from Epsom salts.

Some use long-lasting products like Osmocote, mainly for convenience. These products consist of fertilizer encapsulated in a timed-release substance. One application will last an entire season. I fear this leads to a risk of under- or over-fertilizing, because I no have control over the rate of distribution: hot, wet weather can cause some of these timed-release products to decompose faster.

There are now newer products with a coating that is supposed to be less susceptible to premature breakdown. A product called Nutricote is now being touted as none better. It's not readily available, with two known exceptions: direct from the manufacturer in 50-lb. bags (call Florikan at 336-421-5457) and under the label "Dynamite" in much smaller bags at Home Depot. It's available in various strengths and lengths-of-duration. You should choose the duration type carefully, based on your needs and length of local growing season. I have selected their 17-7-8 plus "minors" (a collection of minor elements) in a 140-day duration formula to try this year.

Another product I have used is a once-a-season Scott's Pro-Gro 18-3-6 with minors. It is designed as a top dress fertilizer and contains controlled-release NPK along with magnesium and micro nutrients. It is advertised to last 2-3 months in the South and 3-4 months elsewhere.

You should avoid indiscriminate application of supplemental micro nutrient products. Micro nutrients can be beneficial, but the threshold between beneficial and toxic is very small. If you want micro nutrients, the best advice is to buy a fertilizer that comes with them in appropriate, balanced proportions, or know exactly what you need and follow directions carefully.

Some years I instead use a monthly application of a foliar spray. Frequent, diluted applications means less risk of applying too much at any one time. Having said that-even with foliar feeding you can overdo it. Sprayed fertilizer is readily absorbed and fast acting. Foliar feeding can be a more efficient use of fertilizer, because about 90% of the fertilizer is absorbed by the plant. In soil application, this level drops to only about 10%.

I'm not aware that the actual brand is that important. I use any brand name fertilizer, such as Peters, Miracle Grow, or Dyna-Gro.

Do not apply fertilizers too early in the spring. Otherwise, your plants may jump to life only to be damaged by a late freeze. This may contribute to a condition called 'spring sickness' in daylilies.


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