Ask Erik - Letters to Maximum Yield

Hello.. Love your magazine.. I was wondering if you could answer a few questions for me First. Do you suggest stripping off most of the leaves on the plants after a few weeks into bloom so that the flowers get the maximum light? People have varied opinions.. And should leaves with a reddish purple stem by trimmed off? Finally, do you recommend using Dr. Willards on a daily basis on the leafs?? Thank you in advance and keep up the good work... Vic.. Coq...

Vic,
Thanks for the compliments. A few factors will determine how and if any leaves and stems should be removed.
Firstly, the height of the plant and the amount of available light are a major consideration. For taller plants, greater than 3' with about 50-65watts per square foot (for example, a 1000W H.I.D. lamp over a 4' X 4' area) about the bottom 1/3 of the plant can be pruned. If plants are widely spaced, with lots of room between them, you may not want to do this at all. The lower leaves have stored energy which the plant will transfer to the final bloom near harvest. However, if these leaves are receiving little light they will dwindle and die prematurely, at the expense of better air circulation through the plant canopy (if not removed) and stealing valuable nutrients and energy from the more active points in the plant canopy. If growing short day plants (requiring 12 hrs of darkness to flower), these trimmings can be rooted under 24hrs of light and will revert to the vegetative stage producing a bushier, highly branched plant for your next crop.
If growing shorter, single stemed flowers 1-2.5' in height with lighting as above, the lower leaves need not be removed because the plant should be receiving near equal light intensity from top to bottom, producing more uniform and consistent results. Make sure that there is good air circulation within the plant canopy with dense plantings. The lower leaves should never remain moist (often a problem in growing with uncovered peat based mediums in tables).
So far as spraying with catalyst altered water (Willard's) every day, this could become a problem later in flowering. Sunscald can always be a issue, but mainly is that water sits on the dense flowers or dense canopy for long enough for pathogens, such as blights and mildews to enter. Pooled moisture on leaves or flowers for prolonged periods is a gateway for these pathogens (often obeseved with flowers touching walls).
Experiment with different types of pruning on a couple of your plants to best determine what works for you.

Cheers, Erik Biksa

Hello. I'm wanting to know would you recommend adding more light in my 10x12 area because I've read that more light means more yield in the end? I'm working in a 10 x 12 room with around 16 plants in a 4 x 5 area just under the light which is a 1000 watt HPS lamp. The area is well ventilated and has plenty of co2. What's your advice on this. Thanks for your time and energy,
Brian. Thanks Brian, sounds like a nice little set up. You have a large volume of air to buffer temperatures, etc. which often means healthier plants. If you only intend to utilize 4' X 5' of your space, your current set up would supply you with high light intensities (the light should be about 18" above the canopy), resulting in greater yields, larger flowers, more marketable plant material, etc. If you are still in the vegetative stage or have just begun flowering (and you have an unquenchable appetite for your produce), you might consider adding another light and spacing the plants further apart, using more of your space. I would recommend that you simply set up another 4' X 5' area. If you need 8 weeks of flowering, space the two areas 4 weeks apart (a seperate light tight area for vegetative growth is required) and you will be harvesting every month. Add a third station and you can harvest every 20 days, etc. Or mount the three lights to a three arm SunCircle or SunTwist, and harvest the motherload all at once. You can still use the light movers for perpetual harvests, just make sure that your "stations" can be adjusted to the fixed height of the lights. Also remember that as more lights are added, more heat is generated which must be exhausted or exchanged.

Good Luck, Erik Biksa

first up you put out a great informative magazine ,i wish i had been handed sooner.i have read with interest on your u.v ozonation..i have a room 3mts x 3.6mts and produce 1 1/2 to 2 lb per plant with 4 plants in the room.yes,rank smell is chronic can one of these u.v ozonators placed in this room be effienct enough or would i also have to set up the corona set up threw my exaust fan as well..also can you get a automatic ph monitor kit so that it can adjust the ph itself for a more consistent level.also interested in a co2 hand held monitor ,when is the best time to check co2 ,5 minutes after gas release or just before the next cycle.where in australia can i aquire these tools of trade.thank you for your time..ruckus

Nice to hear from somebody in your neck of the woods, Ruckus.
You have a large growing area for four plants. With this large volume of air, and assuming your plants do not take up the majority of the area, a smaller U.V. sterilizer might do the trick`. If it is to be placed within the growing room, and assuming it is not occupied by humans, a 15" bulb may be enough. Typically, a smaller output is prefered, but high humidity and heat lower the output. This bulb must be in a light tight unit. You can permanently damage your skin, lungs, and eyes with exposure. An eco-badge will indicate if ozone levels have become harmful. Also note that the ozone within the grow room may diminish some of the flavours and aromas that you enjoy. It would be better to have this bulb in your exhaust ducting, if the output was not enough, simply install an additional bulb. Take care where the exhaust travels to, as not to expose anybody to potentially harmful ozone. Activated charcoal can further remove odours from the air, and can be used within the growing environment and is very safe. For larger odour problems corona discharge types installed in the exhaust system are the way to go. Extensive ducting is required as the ozone generated must get a chance to mix with and oxidize the offensive air before exiting. Most units require monthly maintenance. As for the pH, installing a float valve in your reservoir will dramatically stabalize your pH. If after topped up with water, if it is still out of range, nutrients have been removed and must be replenished. Commercial dosing units are available from companies such as Hanna. Commercial aquariums may also require such units. Be careful, if it goes on the fritz you could give your plants an acid bath. Some have daily limit set points to help prevent this. An infrared CO2 "sniffer" can be used to acurately monitor and replenish CO2 if it should fall past the set point. For testing at the plant canopy the glass vial testers can be used, but are not cost effective if used frequently. You should measure the CO2 levels at various times through out the light cycle and look for trends and patterns to help determine the average injection or combustion duration required. Hand held meters are also available from scientific instrument supply companies such as Hanna. As for retailers, check out the merchants section in the back of your Max Yield for a store near you. Many should be able to supply via mail order, but if you intend to spend the money, make sure you know exactly what your getting.

Thanks, and nice to hear from you, Erik Biksa

dear webmaster,

i am a newbie and i learn that some elements could inhibit plant absorbtion of another element if it is in excess or reaches toxicity level. to prevent this, ratios are suppose to be followed. like in the case of Mg and Ca. the Mg level should be somewhere between 20 to 30% of Ca to grow leafy veggies, the best NPK ratio is said to be 1 : .2 : 1 (Howard Resh) the list is said to go on ... can you give me more idea on this ratios ?

thanks

klique

Klique,
From your question, it sounds like you are catching on fast for a newbie. Yes, most plants should have a 3:1 ratio of Calcium to Magnesium, in hydroponic solutions 150ppm Ca and 50ppm Mg work well. More potassium is typically required by flowering leafy plants than vegetative leafy plants. A good overall ratio such as 1-1.5-2 of Nitrogen to Phosphorous to Potassium works well for the macronutrients for flowering. Note that fertilizer labels list P (phosphorous) as P2O5 (phosporic anhydride) and K (potassium) as K2O (potash). The ratios mentioned, and likely Dr. Resh's, have been converted. The ratio you mentioned would work well for vegetative growth.
Other microelements should change proportionatly with the macro elemnts (NPK). As phosphorous increases during the bloom phase, zinc and iron should also be increased. Formulas that take advantage of more than one form of micro nutrient source are best, as the element is then available through a wider range of conditions.
Magnesium levels and potassium levels should also gradually increase through out flowering, while nitrogen decreases. Different plants have different needs in different environments. Ratios can be used for feeding requirements but are not the absolute. Closely monitoring your plants, checking TDS, pH, etc and using a high quality fertilizer, as per a good, detailed feed chart will help you harvest a successful crop. General Hydroponics offers a comprenhensive 3-part solution, allowing you to tailor feed the plants. Grotek has introduced a 2-part series called "Liquid Life" that has been formulated to adjust to the plants requirements using a simplified feeding program. The results look promising. There are many high quality hydroponic and specialized nutrient solutions on the market. You can also learn to blend your own, although prepared solutions are prefered for convinience and less room for error.

Bon Appetite, Erik B

g'day guys. I have a urgent problem, i am growing from a strain and they are about 25cm tall, and four sets of branches out. the prob is cupping of the leaves towards the end of the day,slow growth,and not drinking much. they are seedlings not clones. My running conditions are: feed, 1500ppm, being water 360ppm, nutrients1140ppm,=1500ppm, ph=5.5-6.5, air temp=26c,morn-34c,night just before turn off when cupping is at its worst. tank temp=26-30c, they are looking ok in morn, but as day goes on they start to cup upwards from the sides of the leaves almost like the closing of a book. everything else seems ok (ie) greeness,robust, normal leafs,etc, woul hope to get a reply a,s,a,p. all the best. yours sincerly, thanks .

Thanks for the email.
Firstly, it sounds like you are dealing with water high in calcium and magnesium carbonate and possibly sulfer ("hard water"). If the fertilizer you are using attempts to supply these element assuming they are not present to begin with, you can reach excess levels. When this occurs, nutrients such as phosphorous can become unavailable. You can use commercial fertilizers such as General Hydrponics 3 part nutrients, with their "hard water micro" formulation. You can also get a water test to determine how much of the above mentioned elements are supplied by your water and create a nutrient solution around those quantities.
Or try the following hardwater bloom nutrient formula:

per U.S. Gallon (3.785 L) water

2 grams Monopotassium Phosphate (0-52-34)
2 grams Potassium Nitrate (Salt Peter)
2 grams per 10 gallons Chelated Trace Element Blend

*Adjust strength to 1200 ppm or as required.

The above should work, and with some adjustments may prove to work well for you.

Your overall nutrient strength is too high for the temperatures you describe. Flush the system with plenty of fresh water. Use distilled water if posssible. Try running your nutrient solution at quarter to half of your current overall strength. You can coil stainless steel tubing and place it in the reservoir. Cold water is then circulated through the coils, allowing more oxygen to be held in the water (dissolved oxygen) for healthier root systems. Pythium can be problematic in the conditions you describe. Inline U.V sterilizers can help prevent pythium from developing. You may have developed "soft" growth from the excess of high soluable nitrogen and high temperatures. Plants are then more susceptible to disease. Potassium Silicate can help to strengthen cell walls and protect against draught, but will typically decrease the % dry matter, as it tend to retain moisture within plant material.

If I was going to set up a large hydrosystem, what system would be the best to use? How can I contact a distributor? Who is the manufactor of the system? Would an NFT system be the most productive and lucrative system? Is there anyone I can contact for literature?
PS: I'm looking for the best most cutting edge available equipment.

It sounds like you want the "Ferrari" of hydrosystems. Most high-performance systems are tempermental and require a respectable level of understanding. However, well written instructions and feed charts can introduce less experienced growers to incredible results. Large scale systems are available commercially, or can be constructed from well sourced materials. There are many advertisements from reputible companies in Maximum Yield, visit one of their websites or request information to a mailing address. With regards to particular systems you may consider the following: N.F.T. systems can be very productive. Most tend to be manufactured for plants with smaller root systems. For larger plants, increased air space around the roots for gas exchange is preffered. With larger root systems and longer channels, nutrient gradients and decreased dissolved oxygen levels at plant sites further from the point of solution injection may occur. Plants producing significant mass will require additional support. Be careful of high root temperatures. Water based systems utilizing larger volumes of faster moving nutrient solution with several points of injection can overcome some of the draw backs associated with earlier N.F.T. systems. Rockwool with drip irrigation or the more simplistic flood and drains systems can be very productive. Growing in rockwool usually requires some experience or research for impressive results. For plants taller than 3' in finishing height and widely spaced, a bucket system is very well suited. It can easily be constructed using opaque 5 gallon poly buckets with lids and is less tempermental to operate. Look for systems that are founded on tried and true principles of hydroponic plant production to ensure results and try not to be in a rush if you can help it.
When in doubt with your new system consider contacting the manufacturer or drop me a line!

Good Luck, Erik B

Hey Guys,

I need some sound advice - as there are so many conflicting opinions out there. I am running what would be considered a fairly satndard indoor operation and am enjoying considerable success. I am now looking at how to fine tune it. Firstly, at what stage do you recommend feeding nutrients (as opposed to just water) to new cuttings of the Semi- Hardwood (wink wink) variety ??? I don't have any majhor hassles with them, but my average time to get roots is 2-3 weeks plus. As I live in Sydney, temperature is not an issue. Other locals assure me they have consistant averages of 10 days or less !! My second question is, do you think there is any benefit in using additives such as 'BUDSWELL' in the final weeks to increase yield - if I am using the 'General Hydroponics - FloraSeries' nutrients as recommended ??? Do you think these type of additives are largely snake oil ??? Cuttings taken from older, woodier plants may take longer to root. Most growers tend to feed mothers a steady dient of nitrogen to keep them productive, If the cuttings are taken at a time of high nitrogen concentration in the plant tissue, particularily in the ammonium form, longer rooting periods are typicall. Feed the mothers nitrogen primarily in the nitrate form and replace them when they become woody. Always take your cuttings with clean instruments, pre treated medium, sterile trays, and a quality rooting compound. Getting cuttings into the medium as quickly as possible after slicing off with a clean razor or scalpel is critical. If taking many cuttings at once, store them in a tub of very mild nutrient solution and B-1 until they can be recut and set into the medium. Bottom heat (75-80 Degrees farenheit), 80-80% humidity, an occasional air exchange, foiliar sprays, and good drainage are factors.

Pretreat with a mild nutirent solution higher in phosphorous and potassium (also avoiding ammonium if possible) as per the manufacturer's directions that has been adjusted to compensate for the initial pH of your rooting medium. Nutrient concentrations can be up to 300 ppm, but is generally applied every other irrigation allowing for some run off. Take care not to overwater, and occasionally squeeze some solution from the medium and test the pH.
If using General Hydroponics Flora series as recommended and you are meeting other requirements bloom enhancers may not be of value or can be detrimental depending on the particular requirements of your plants. If you decreased the concentration of all the "ingredients" of the "brew" to achieve the same total TDS levels you may or may not discover any yield enhancing potential, particualrily in water based systems, which tend to follow formulas rather than recipes. However, results are more likely to be noticible in soilles mix, pariticularily towards or combined with the "flush" period. This is not to singal out any particular products but is to be used as a general rule of thumb.

Regards, Erik B

If I was going to set up a large hydrosystem, what system would be the best to use? How can I contact a distributor? Who is the manufactor of the system? Would an NFT system be the most productive and lucrative system? Is there anyone I can contact for literature? PS: I'm looking for the best most cutting edge available equipment

It sounds like you want the "Ferrari" of hydrosystems. Most high-performance systems are tempermental and require a respectable level of understanding. However, well written instructions and feed charts can introduce less experienced growers to incredible results. Large scale systems are available commercially, or can be constructed from well sourced materials. There are many advertisements from reputible companies in Maximum Yield, visit one of their websites or request information to a mailing address.
With regards to particular systems you may consider the following: N.F.T. systems can be very productive. Most tend to be manufactured for plants with smaller root systems. For larger plants, increased air space around the roots for gas exchange is preffered. With larger root systems and longer channels, nutrient gradients and decreased dissolved oxygen levels at plant sites further from the point of solution injection may occur. Plants producing significant mass will require additional support. Be careful of high root temperatures. Water based systems utilizing larger volumes of faster moving nutrient solution with several points of injection can overcome some of the draw backs associated with earlier N.F.T. systems. Rockwool with drip irrigation or the more simplistic flood and drains systems can be very productive. Growing in rockwool usually requires some experience or research for impressive results. For plants taller than 3' in finishing height and widely spaced, a bucket system is very well suited. It can easily be constructed using opaque 5 gallon poly buckets with lids and is less tempermental to operate. Look for systems that are founded on tried and true principles of hydroponic plant production to ensure results and try not to be in a rush if you can help it.
When in doubt with your new system consider contacting the manufacturer or drop me a line!

Good Luck, Erik B

I'm interested in setting up a small comercial hydroponic system for strawberries. An NFT seems to be the way to go. Can a strawberry crown with roots, like what you get from a nursery, be placed directly into an NFT system to start it? Can an NFT system be set up outside in warm weather? Any info/pictures would be greatly apreciated.
Thanks,
Dirk Marshall

Dirk,
Yes, strawberries can do very well in an outdoor N.F.T. system. There are many commercial growers using this technique in Australia, you may consider locating them and contacting them for particular advice via the internet. To help keep the plants and the nutrient solution from overheating, shade cloth is suspended and secured over the growing area. Depending on the intensity of light and heat, shade cloth from 30 to 70% shading may be used. Aluminized materials help reflect more heat away from the crop, and can help retain warm air on cooler, clear nights. The cloth also protects the berries from hail, reduces wind, can discourage birds and other pests, and will reduce the size of rain droplets, reducing fruit losses. Look for a professionally designed shade enclosure. The nutrient solution can be heated and chilled to extend and modify the growing season. I would not recommend starting the crowns directly into the system. They may begin to rot if not in an actively growing state. Keep them in trays (likely in net pots) and irrigate occasionally until they begin to grow, before transplanting them into the system. An "A-Frame" layout for the troughs will make the most efficient use of space within the enclosure. Planting densities of greater than 100% may be achieved. Vertical columns take advantage of the strawberries natural growth habits. Research the varieties available, as some will be better suited to hydroponic cultivation than others. You may experience higher root temeperatures growing hydroponically outdoors, so disease resistance is a factor to consider when selecting a variety.

Good Luck, Erik B