Water Quality and Fertilizer for Orchids
Compensate for Alkaline Water with Fertilizer

Choose Your Fertilizer Based on Water Quality, Sue Bottom, SAOS
FirstRays.com Fertilizer Calculator

pH Management and Plant Nutrition, Bill Argo, Blackmore Co. Journal of the International Phalaenopsis Alliance

Part 1 Intro
Part 2 Water Quality
Part 3 Fertilizers
Part 4 Substrates
Part 5 Choosing the Best Fertilizers

Peters Complete Guide to Fertilizer Selection

Peters has a great selection guide to help you match up the proper fertilizer for your water quality.
- For low to moderate alkalinity water or if you grow in a highly organic mix like bark or coconut, use Peters 15-5-15 Cal Mag fertilizer available from SAOS (we're looking for a source for 17-3-17 Peat Lite Neutral Cal Mag).
- For high alkalinity water, use a 20-20-20 available from retail outlets and SAOS with monthly epsom salts applications (we're looking for a source of 18-8-17 Peat Lite High Mag Special).

Michigan State University (MSU) Fertilizer
Without High Phosphorus - A New Fertilizer for Orchids

It is hard to find good fertilizer at the big box stores. Look for a low urea fertilizer, one with an even balance between the ammonia and nitrate form of nitrogen (the first number), one with a lower middle (phosphorus) number, and one that contains calcium, magnesium and micronutrients. You can order a MSU fertilizer for well water from First Rays.