Questions & Answers
Use the contact form to submit your comments or questions. Not all questions will be answered. Consider joining and submitting questions to the Kratky (Passive Hydroponics) Facebook group for answers from a wide range of people.
My tomatoes are getting dark spots on the bottom of the fruit. What should I do?
Blossom end rot is a common problem especially with the first fruits of a plant. The problem is complex and simply adding calcium is not always the solution.
This article goes into depth about possible causes and remedies. |
I'm using LED panels for lighting and a fan for air circulation. Is this still the Kratky Method?
I think you're wrong about the large reservoirs. I'm growing a ___ (large plant) in a ___ (small) container and it's doing just fine. Not everyone has the space for such large containers.
Every growing situation is different and what works for one person might not for another. That said, is your plant producing fruit? Plants that produce fruit use much less water in the early stages than they do when fruiting. As mentioned, Dr. Kratky's research suggests a large tomato plant may consume 5 gallons (20 liters) per pound (454 g) of fruit it produces. Some people have written to me saying they're growing a tomato in a 50 gallons (200 liters) reservoir and still need to refill the reservoir a fe gallons at a time so as not to damage the air roots. There is little downside to erring on the side of a larger rather than a smaller reservoir other than the space it occupies and perhaps cost of nutrients. In the end, the plant will be less stressed and the grower will work less when a larger reservoir is used. Grow the plants that you have room for. If you live in a smaller space, grow smaller plants! You may also want to research DWC or float valves as a way to use a smaller reservoir with a larger plant.
|
You use Rubbermaid Roughneck totes and pool noodles. Are those safe for food?
Rubbermaid Roughneck totes are made from Low Density Polyethylene. LDPE has good chemical resistance, high impact strength, and strong wear absorption. Like PET and HDPE plastics, LDPE can hold food products without leaching any harmful materials or allowing microorganisms to permeate. Pool noodles are made from polyethylene foam and they touch only the stem of the plant, so there is no contact with the foliage or fruits. That said, polyethylene foam is a common type of plastic that has long been used throughout the food packaging industry due to its non-toxic properties. It has a very simple molecular structure that does not require chemical additives unlike vinyl / PVC.
|
I can't put a roof over my plants that I'm growing outdoors so rain is an issue. I'm going to drill a hole in my 5 gallon and 2 gallon buckets and use that hole not only for drainage but also to refill the buckets since I'm growing mostly tomatoes. I'm totally flummoxed on WHERE to drill the hole! (on the side of course - but location below the net cups. Just a little below or 3 to 4 inches from the bottom or ????
Rain on Kratky buckets is a real problem. This solution isn't something I've personally done (I found it easier to build a roof), but my understanding is as follows: Drill a small hole (about 1/4" or 6mm) approximately half way up the bucket. We want a small hole so the moist air space does not dry out. Cover the hole with electrical tape or insert a cork when the system is beginning and the reservoir is full. When the nutrient water level reaches that halfway point, you can remove the covering and if it should rain, the top half of the roots will not be submerged. Ideally, adjust the nutrient levels after a rain as they will become diluted.
|
I would love to try bush green beans using Kratky. How big of a container should I be using for the beans? Can I use the 5 gallon HomeDepot bucket to plant them? How many plants is suitable per bucket?
Beans will grow in net pots in a bucket, but they seem to like some soil. For a 5 gal bucket, probably 3 plants would work fine. Grow them just like lettuce. They probably won't grow as well as they would in soil. Dr. Kratky has a nice video here about some pole beans he grew in Hawai'i using coir and a sub-irrigated system. It isn't the traditional "Kratky" (suspended net-pot) system, but it is passive as no pumps or electricity are required.
|