PLANT NUTRITION PROBLEMS CAN BE SOLVED BY THE APPLICATION OF SCIENCE

Since perlite is devoid of available nutrients, the liquid feed applied to hydroponically grown plants is their only source of nutrition. This solution must therefore provide all the essential elements required for healthy growth and development. Moreover, each individual nutrient must be added at a rate which exactly matches its removal by the crop if deficiencies or toxicities are to be avoided. Thus, potassium may be added at a concentration of 400 mg/l, molybdenum at a mere 0.04 mg/l. Yet despite the 10,000-fold difference in concentration, molybdenum is just as important as potassium; without it there would be complete crop failure.

THE PERLITE CULTURE SYSTEM

When used for commercial crop production, perlite is contained in 20 to 30 liter perforated bags designed to hold three tomato plants. A constant supply of aerated nutrient solution is maintained in the perlite by sitting the bags in a shallow reservoir of solution formed in the bottom of an outer polyethene gully by a series of polystyrene dams. Perlite's strong capillary attraction for water automatically draws up water from the reservoirs at the same rate as it is lost by evapotranspiration, irrespective of weather conditions or stage of crop growth.

THE IDEAL ROOTING MEDIUM

Expanded perlite is physically stable and chemically inert. The porous nature of the cellular granules ensures a product that is light to handle, holds large quantities of readily available moisture and has a strong capillary attraction for water. Since it is free draining, it is also well aerated.

Its neutral pH, negligible nutrient content and a complete freedom from pests, pathogens and weed seeds combine to make this an ideal rooting medium for hydroponic culture.

WHAT IS PERLITE?

Perlite is a volcanic glass formed when larva cools very rapidly trapping small quantities (2-5%) w/w) of water. When the glass is crushed and heated to about 10000C, the trapped water vaporizes and puffs out the softened granules to form white mineral foam.

GROWING HYDROPONIC CROPS USING PERLITE

HYDROPONICS--- Hydroponic growing systems are based on a new generation of superb rooting media - inert, sterile, uniform materials such as the mineral perlite and rockwool. These products act merely as supports for a complete nutrient solution on which the plants depend entirely for their water, mineral nutrients and oxygen. In the purest form of hydroponics, there is a complete absence of solid substrate, the nutrient solution itself acting as the rooting medium.

Commercial growers can choose between three main hydroponic systems: one which uses a recirculating solution, the nutrient-film technique (NPT), and two 'static' systems, perlite culture and rockwool culture. The perlite culture system was uniquely devised and developed by a team of Scottish horticulturists. It is now the most widely used glasshouse crop production method in Scotland and it has the fastest growth of any hydroponic technique in the U.K. It is currently the subject of worldwide interest, particularly for use in arid zone regions.

FEEDING AND WATERING

Potting Soils as a Medium

Gardening with potting soils provides beginning growers with a simple, straightforward way to try out hydroponic gardening. Plants grow in nursery pots and can be watered by hand, eliminating the need for pumps, timers, and water systems.
Potting soils may look like garden dirt, but they are "soilless mixes", made with peat, vermiculite and perlite. Because these materials are acidic, potting soils also contain a very fine powdered dolomite lime to balance the PH of the mix. Since nursery pots restrict air and water movement, potting soils are a "chunky" texture to keep roots healthy.

These soilless mixes contain no fertilizer - you use hydroponic foods (dissolved in water) to supply plants with all the nutrients they need.


Here are some guidelines for gardening with potting soils:
1) Use a good-quality potting mix
Some "mixes" are pure peat moss! Your hydroponic supply store can recommend a good potting mix. Many growers use commercial growers' potting soils since they are top-quality mixes. For small (one to two gallon) nursery pots, use "Sunshine #1" Mix; for larger (three gallon or bigger) containers, try "Sunshine #4" mix - it's very chunky and won't pack down too much in the bigger pots.

2) Use hydroponic nutrients designed for soilless mixes.
Potting mixes "soak up" some of the fertilizer so manufacturers have developed precise foods for this method of gardening. They are inexpensive, easy to prepare, and your plants will love them! A good "green growth" fertilizer is "Peat-Lite" mix (20-19-18). The numbers refer to the amount of nitrogen, phosphorous and potassium in the fertilizer. These are minerals used in large quantities by plants, called the macro-nutrients. "Peat-Lite" also contains several other minerals, giving young plants everything they need for fast green growth.
Another potting soil fertilizer, for flowering and crop production, is called "Blossom Booster" (10-30-20). Note that flowering plants and plants in crop production use less nitrogen - the first number-but more phosphorous and potassium. The important thing to realize is that there are precise easy-to-use foods available for plants in potting soils for each stage of growth.

3) Use the right size nursery pot
Very small plants can start in a 4" or 6" pot. Soon they will need to be transplanted to a one gallon nursery container later. This is how to check if plants need a larger pot: Slide pot away from potting soil to check roots. (The pot will slide off easier if the soil is not soaking wet). If the roots are showing on the outside of the soil, and they are starting to wind around between the soil and the pot, it's time to move plants to a larger nursery pot. Plants that are kept in pots too long develop long, winding roots - they are called "root bound" or "pot-bound" plants, and they often dry out very quickly. Even when pot-bound plants are transplanted to larger containers, their winding roots are slow to spread into the new potting soil. Transplanting crops before they're pot-bound helps the roots to spread quickly into the new soil. If you see any of these signs in your garden:
- Plants dry out quickly between watering.
- Soil shrinks away from container, leaving an air space between soil and nursery pot.
- The soil surface collapses, forming a bowl shaped depression on the top of the soil.
- Surface soil forms a hard "crust". Water can't flow through this crust: it just runs off the top of the soil and over the side of the nursery pot.
Then it's repotting time! Here's a general guide for repotting for fast- growing plants: 4" to 6" round or square pots - repot after 2-3 weeks into 1 gallon pots. 1 gallon pots - repot after about 4 weeks into 2 or 3 gallon pots.
Remember, this is only a general estimate - your plants might grow faster or slower, so sliding off the nursery pot to check root growth is always the best way. Remember to moisten the new soil before re-potting, and water the plant well when you've finished to settle it into its new container.

4) Feeding and watering
- Never fertilize dry plants - water well first and feed 1/2 hour later to avoid "burning" roots.
- Always use room temperature water. (21*C=70*F)
- Feed your plants today, then use plain water the next time they are dry.
- Water well to moisten the entire root system, then allow pots to drain excess water.
- Let plants dry a bit between watering, so they're not waterlogged.
- If plants are wilting, you waited too long!

Why you should alternate watering and feeding:
When you feed your plants, some of the fertilizer is "sucked up" by the potting mix. If you fertilized every time, the nutrients would build up in the potting soil and damage your plant's roots. When you give your plants plain water between feedings, it re-dissolves the fertilizer in the potting soil, making it available to the roots and helping to avoid fertilizer build-up. Using the "feed-water-feed-water" method keeps roots healthy and satisfied while the top growth gets all the minerals it needs. Other hints":


- Keep nursery pots off cold concrete floors - cold roots mean very slow growth!
- If soil packs down, loosen it gently with an old kitchen fork.
- Plants in the same pot for more than 6 weeks may benefit from an addition of very fine dolomite lime - use one tablespoon dolomite for a one gallon pot, two tablespoons for a two gallon pot and so on.

FEEDING AND WATERING

Always use room temperature water

Never fertilize a dry plant - water it well and feed an hour later

In hot weather conditions - feed only every third time you water (90 degrees F or higher) and reduce Nitrogen feed by a third in hydroponic systems

Let water stand overnight or stir it to drive off excess chlorine

For plants in soil or sunshine mix:
- feed every other time you water during normal growing conditions
- add dolomite lime (one Tablespoon per gallon of soil) as a top-dressing to soil and work it into soil after 2 months of growth

For plants in hydroponics:
- watch PH and food strength. It really helps!
- flush with straight water in hot weather

GROWING IN SUNSHINE MIX OR PRO-MIX:

(a) These soil-less mixes hold a lot of food.

(b) Feed every second time you water.

(c) When you use plain water you re-dissolve the food held by the potting mix and make it available to the roots.

General Tips

When setting up and maintaining your cloning box you must take care to provide your clones with the best propagating environment and care possible. To ensure fast rooting and high success rates, high humidity, 16 - 18 hours fluorescent light, proper air circulation, strict attention to cleanliness and correct bottom heat are absolutely necessary.

Humidity should be 80-85%. If air in cloning room is dry mist more often. Black leaf edges, black spots on leaves and mushy stems (damping off disease) are all indications of too much moisture and poor airflow. It is also essential that you provide adequate bottom heat. Do not try to skimp here. The cuttings and their cubes should be warm 24hrs per day. Often people fail to clone successfully because they do not provide bottom heat and clones will root poorly when nightime temperatures dip under twenty degrees centigrade.

Remember: Stress is bad. The faster your cuttings develop roots, the less stress they will undergoe. Any stress the cuttings are exposed to can result in a decrease of final yield by up to 50%. So treat your cuttings with a lot of T. L. C.

In emergencies: If you have to take cuttings from blooming plants, cut all the flowers off the cuttings. This will reduce stress. If planting clones outdoors treat with care and slowly acclimatise to the sunlight. Clean trays thoroughly between cycles. Use a weak bleach solution and water. Lots of bacteria and fungii spores can grow in dirty wet trays. This will lead to damping off disease. Remember cleanliness is very important. Do not resue growool cubes after they have been used throw them out and buy fresh ones they are inexpensive easy to store if kept dry. Do not clone from mother plants infested by spider mite. Keep your mother plant free of spider mites. Your cuttings will have little or no resistance to spider mites and will stress badly if attacked by the mites during cloning.

FLOWERING & CROP PRODUCTION PLANTS:

Plants that are producing flowers or fruit or that are large enough to begin crop production:
(1) Flush the root zone by gently running room temperature water through the roots. Large plants could require up to a gallon of water. This clears the soil of any leftover fertilizer from the "green growth" stage.

(2) Use "Flower Food" formula for flower and crop production. First time feed at half strength.

3/4 teaspoon Calcium Nitrate "B" (5 grams) (use only 1/2 teaspoon/gallon in hot growing conditions) 1-3/4 teaspoon Flower Food "C" (12 grams) and stir well. Feed as required. Remember to flush the roots with plan water regularly.

For soil-less gardening in gravel, lava rock, rockwool and clay pellets

BABIES:

New rooted cuttings or very young plants from seed.

Feed: 1/2 strength Flower formula
1/3 teaspoon Calcium nitrate "B" (2 grams)
Dissolve in one gallon warm water, then add:
1/2 teaspoon flower food "C" (3.5 grams) and stir well. Feed every second time you water your garden


YOUNG PLANTS:

Plants in rapid growth with established root systems.

Use a food especially designed to promote vigorous green growth. (First time - feed at 1/2 strength)

1 teaspoon Calcium Nitrate "B" (6.5 grams)
Dissolve in one gallon warm water, then add 1 teaspoon Hydroponic Food "A" (8 grams) and stir well.

Feed as required and flush the root zone with lukewarm water regularly, especially when garden temperatures reach 90 degrees F. (32 degrees Celsius)

Cloning - The Cloning Kit

To begin successful cloning you will need the following items in your kit:

> Fluorescent fixture with two full spectrum fluorescent tubes per fixture.

> 280mm x 340mm Drip Tray, Seedling Tray and Plastic Grow Top.

> Growool Propagation Blocks - up to 3 fit a standard nursery seedling tray.

> Hormone rooting compound such as "Clonex", "Eziroot", or "Rootex-L".

> Heating pad or propagation mat.

> Superthrive - anti stress agent.

> Plant Root Zone Accelerant - hormone to enhance the development of roots.

> Reputable nutrient solution and a thermometer.

> Timer.

> New razor blade single edge and pruning shears or sharp scissors.

> Spray bottle for misting clones.

How To Take Cuttings

Before you begin to take cuttings, it is a good idea to have all the equipment ready and in good working order. All equipment should be thoroughly cleaned and the cloning area should be as sterile as possible.

Step 1. Rinse the propagation blocks with a half strength nutrient solution to which has been added 4 drops of pH lower per two litres. Let propagation blocks soak for up to 10 hours prior to cloning in this solution. Discard soaking solution and just prior to cloning rinse blocks again with 4 litres of half strength warmed nutrient solution to which has been added 4 drops of Rootzone Accelerant and 5 drops of Superthrive. Insert thermometer into cubes and allow temperature to reach the green zone before cloning commences. Temperature should be maintained day and night within the range of 20 to 30 Cent if cloning is to be successful.

Step 2. Select cuttings - cuttings can be taken from anywhere on the mother plant provided the stem is of the correct thickness. Stem thickness should be between 4mm to 6mm diameter. Take cuttings with about four sets of well developed leaves and approx 100mm to 150mm in length. The topmost growing shoots make excellent cuttings however make sure the wood is of the correct thickness and not too green or to woody. You may wish to take a number of cuttings at one time immerse them in an ice cream container, or similar, filled with tepid water to which you have added a few drops of superthrive anti-stress formula.

Step 3. Take the single edged razor blade and begin trimming your cuttings. Take cuttings one at a time from tepid water and now trim bottom two sets of leaves flush with stem. Trim approx 50% of leaves by cutting across the leaf surface. It is hard for the cutting to keep these large leaves alive and they usually wilt and fall off if not cut in half. Cut the stem at fourty five degrees across the bottom leaf nodes. Gently scrape the cut area around the bottom of the stem. This disrupts the cells on the stem surface and helps them change into root cells. Take whatever rooting hormone you have purchased and dip the bottom of stem into your rooting compound. Here is a tip: Do not dip directly into rooting hormone bottle instead pour some off into a small container such as a thimble and discard what is not used. This saves you introducing any bacteria or disease into main container. Store main bottle of rooting hormone if refrigerator after opening.

Step 4. Now you are ready to put the cuttings into the growool propagation blocks. Gently insert the stem into the cube making sure the stem does not protrude out of the bottom of the cube. After all the clones have been prepared and placed in the propagation blocks you may water the block again with half strength nutrient solution to which you have added Superthrive and Root Zone Accelerant. Water the blocks until nutrient freely runs from the blocks allow to drain for a few minutes then place blocks inside the cloning chamber and place the chamber over the heating pad. You should close the vents on the grow top for the first 3 days. Check moisture and temperature for the first couple of days and mist cuttings morning and night with water to which you have added a couple of drops of Superthrive. Be careful to ensure that you do not have water sitting in bottom of tray. Growool cubes should be able to freely drain at all times. Place cloning chamber under flourescent fixture for approx 16 - 18 hours per day.

Step 5. After three days open the vent on the Grow Top. Monitor progress of clones for another 4 to 5 days by this stage it should be time to take Grow Top off the unit and expose clones to normal air - still continue misting morning and evening. Again monitor nutrient and moisture levels in the propagation block. By the end of a further 5 to 8 days you should be able to see root hairs protruding from the propagation blocks. Healthy roots look thick, white and hairy. Sickly roots look thin, yellowish or brown and hairless. The clones with the healthiest roots will be the same ones you will be proud of at harvest time.

Step 6. When your cuttings are well rooted and have begun to shoot it is time to transplant them into you growing system. Slowly introduce them to full strength nutrient and place them under a H.I.D. light system. Remember the new clones are tender and exposing them rapidly to a full strength H.I.D. lamp after the fluros would be a shock. Care should be taken to acclimatise your new clones to the brighter light. Start by raising the H.I.D. lamp approx one metre above the clones for the first few days slowly lower the lamp over the next week till the lamp is at the correct height. This will ensure a smooth stress free transition to growing under H.I.D. lamps.

CLONING Step by Step

Cloning involves preparing a small cutting taken from a mother plant, treating the cut stem with a rooting hormone and placing the prepared stem cutting in a cloning chamber. The clone should grow roots and become an independent plantlet exhibiting identical characteristics to its' mother plant. Most soft or semi-hardwood cuttings will have developed roots within a week to ten days.

The name cloning simply stated means taking a cutting from a mature female plant in the vegetative stage and inducing it to grow roots. Clones will replicate the mother plant in every way ie: size, sex, colour, smell, taste etc. It is therefore crucial to have a mother plant of outstanding quality. The newly rooted cutting can be induced to flower immediately, or it can be put under a vegetative light cycle to attain a larger size.

As soon as the clone is large enough you can begin to take cuttings from it. Contrary to rumour, this can be done infinitely without any loss of desired qualities.

The Mother Plant

It is important to choose a mother plant carefully. When selecting a suitable mother plant consider the following:

> Aesthetic qualities, shape, density of leaves, compactness and size.

> Heavy flowering/fruit production.

> Disease and insect resistance.

> Early Maturation

> Clones well and produces strong new plantlets.

It is important to remember that your mother plant should be healthy and stress free. Cuttings coming from a stressed mother plant may root poorly, be slow growing, produce poorly and become mutated. It is important to reinforce that the condition of your mother plant is paramount to the success of your clones. Vigorous genetic stock can be lost by cloning from poorly cared for mother plants. As a general guide do not take more than 20 - 30 % of the vegetative material from each mother plant and do not take cuttings from the mother plant more than three times.

Each time you take cuttings it is a good idea to start a new mother plant from the most vigorous clones. Remember if growing initially from seed to select only the best genetic plants to use as mothers for cloning. Seeds will never produce the same consistent results you can expect from clones.