Not sure on the EC, but those are hi npk ratios.
Too high for seedlings.
The seeds have stored nutrients sufficient to sustain the plants for 10-14 days before
any nutrients are needed.
I am a li'l confused as to how your soils ph got to be 7-8, if the above list is true.(5.-6.5). What is ph of your tap water?..
more notes...
Check Your Water - Crusty faucets and shower heads mean your water is
"hard," usually due to too
many minerals. Tap water with a TDS (total dissolved solids) level of more
than around 200ppm (parts
per million) is "hard" and should be looked into, especially if your plants
have a chronic problem. Ask
your water company for an analysis listing, which will usually list the pH,
TDS, and mineral levels (as
well as the pollutants, carcinogens, etc) for the tap water in your area.
This is a common request,
especially in this day and age, so it shouldn't raise an eyebrow. Regular
water filters will not reduce a
high TDS level, but the costlier reverse-osmosis units, distillers, and
de-ionizers will. A digital TDS
meter (or EC = electrical conductivity meter) is an incredibly useful tool
for monitoring the nutrient
levels of nutrient solution, and will pay for itself before you know it.
They run about $40 and up.
For the veg. period try a N
:K ratio of about 10:7:8 (which of
course is the same ratio as
20:14:16), and for flowering plants, 4:8:8. Check the pH after adding
nutrients. If you use a reservoir,
keep it circulating and change it every 2 weeks. A general guideline for
TDS levels is as follows:
seedlings = 50-150 ppm; unrooted clones = 100-350 ppm; small plants =
400-800 ppm; large plants =
900-1800 ppm; last week of flowering = taper off to plain water. These
numbers are just a guideline, and
many factors can change the actual level the plants will need. Certain
nutrients are "invisible" to TDS
meters, especially organics, so use TDS level only as an estimate of actual
nutrient levels. When in
doubt about a new fertilizer, follow the fertilizer's directions for
feeding tomatoes. Grow a few tomato or
radish plants nearby for comparison.
PH - The pH of water after adding any nutrients should be around 5.9-6.5
(in rockwool, 5.5-6.1) .
Generally speaking, the micro-nutrients (Fe, Zn, Mn, Cu) get locked out at
a high pH (alkaline) above
7.0, while the major nutrients (N, P, K, Mg) can be less available in
acidic soil or water (below 5.0). Tap
water is often too alkaline. Soils with lots of peat or other organic
matter in them tend to get too acidic,
which some dolomite lime will help fix. Soil test kits vary in accuracy,
and generally the more you pay
the better the accuracy. For the water, color-based pH test kits from
aquarium stores are inexpensive,
but inaccurate. Invest in a digital pH meter ($40-80), preferably a
waterproof one. You won't regret it.
