Q: Hi Jim,
Thanks for your prompt reply last week to the questions I posed, I found your answers direct and helpful. I have been reading your book and pamphlets and considering what might be feasible here.
As I explained to you when we were talking water will be a limiting factor - we have 10x22,000 litre tanks installed to collect rainwater and eight of them can be given over to our hydroponics venture. The last 4 were installed earlier this year and the failure of the spring rains means that they are not filled yet but we have that capacity ready for when the rains do come.
I also explained that my passion is to have a productive food garden - producing a large range of vegetables and fruits for the table with the aim of self sufficiency.
We have an east facing verandah 10x4 metres which will be the main centre of our initial operation. The roof is a combination of galvanised iron and laserlite sheets. We plan to install a mesh ceiling for climbing tomatoes to rest on similar to what you have achieved at GardenSmart. Can I grow two tomatoes in an AutoPot™, one a tall growing type like Grosse Lisse and a dwarf Romano type?
Now for some questions about the possibilities of Smart Drippers in normal garden earth. I've already mentioned the lemon tree, a mature 20 year+ tree situated 10 metres from the pressure pump set. A further 25 metres two 5 year old apricot trees and a further 25 metres away to two rows of 1 year old grapevines 35 metres in length. Any delivery problems here - run a main line the length of the run and then take 4mm lines off the main line? What about different needs of different aged trees/vines requiring differing amounts of water. Your material talks about wick size as the method by which flow rate can be varied - what advice would you give about determining the correct wick size in the scenario above? What is the typical litre/day range with the various wicking options? I think I read somewhere that mature fruit trees need a supply of 9 litres/day. What is your view on that figure?
We also have an area 30x16 outdoor area similar to your playground on the eastern side of the house where we would like to employ a number of your grow bags to grow fruit trees, canes shrubs, vines and strawberries. What advice do you have on the spacing of these bags?
Now for some questions about appropriate media to use. The cheapest media I can access from here is scoria. I would hope to use scoria as the main media in grow bags although they wouldn't necessarily have to be the only media used. Perlite (which grade course or fine - which one is best for what?), vermiculite or perlite/vermiculite mix is the most common media used with AutoPot™. As it is sold in litres can you give me some idea of the various capacities needed for the range of your pots. I gathered you use a mixture of media. What advice would you give me about media to use to get a good start with the AutoPot™ system? I realise that you favour a good deal of experimentation, I would like to start with a reliable system to start with and then experiment from there so we would have a good comparison baseline.
I note in your literature that plants such as rhubarb, climbing beans and peas, carrots, pumpkins and bush tomatoes are best grown in the 12" single AutoPot™? Is that correct? Small plants like lettuce, spinach etc in the window style 4 pots. How is the decision made as to which pot to use - the 10" 2 pot AutoPot™ and the 12" single AutoPot™? I understand why you use only water in the CapPlus - how feasible? costly? is it to connect the pressure supply line via a pressure regulator to maintain it at a constant low working pressure. If I was to have my order sent by carrier how would that work?
Finally the Yakon is doing well, as it is a root type plant what sort of container do you advise to grow it in?
A: Glad to hear from you. I am glad to have the opportunity to use my expertise within the water constraints that you (like most people in drought stricken areas) are facing.
Answers to your questions:-
1. Assuming you are referring to the Hydrotray Double 10" module, yes, you can have two different plants in the same tray. You happened to mention Grosse Lisse and Roma tomatoes, I have a few things to add. Grosse Lisse is not recommended for hydroponics due to its tendency to develop blossom end rot. It is best to go for medium sized fruit types, like the Apollo or Mighty Red. Roma are fine in these pots (10"), but this is a bush type (determinate) tomato meaning that no pruning is recommended. It is not suitable for trimming into a single stem to reach the mesh. If you want to use this with the mesh, then you would have to install the tray at the mesh level so that it just spreads over the mesh without having to "climb."
2. Comments on your roofing - I assume it is galvanised sheet alternating with laser lite. This is not 100% due to the 50% light cut off by the galvanised sheets. If you use three or four sheets of laser lite, that would be fine.
3. The Smart-Drippers. There are no problems running the main line to feed all those trees you mentioned - around 100M but the ground level needs to be fairly level. The ground level of the fruit trees should not be more than 10 ft lower or 20 ft higher than the pump level.
4. Smart dripping rates. You are right about 9 litres per tree per day as a guide. There are really no fixed rules on this. In your situation, where water is so limited, it is best to start off with one wick, 15mm wide, per dripper per tree, then evaluate later. In a month or two, you will be able to determine if the tree needs more water by whether they are showing signs of water stress. You should be able to see beautiful new growth, otherwise you can either increase the size of the wick, or add another 15mm wick to the dripper if you feel there is a need to increase the drip rate. At times, giving less water to the tree is fine which is a strategy to limit the size of your fruit tree. Though the trees are smaller, I am certain that you would be able to get a sufficient crop for personal consumption.
5. 30 x 16M playground area. Yes large grow bags are good (200L) each. Spacing depends on the size of the crop. I would put them 3M apart as a guide.
6. Growing media.
- for the 10" squat pots in the Hydrotray Double 10" module - 2 x 10" pots = 5L x 2 = 10L.
- single 12" pot = 10L each
- W/box with 4 pots = 4 x 1.5L each = 6 L
- Hanging baskets = each is 3 L
- for the Hydrotray Double 10" module, scoria can be used. Try to use a mixed size of 5mm to 10mm diam. but needs to free from dust. Good for 10" and 12" pots only.
- for Window box use a good quality potting mix or just vermiculite.
- for Hanging baskets use a good quality potting mix or vermiculite.
- for large grow bags, ideally use bulk potting mix from a garden supplier and mulch the top 2 inches with scoria.
7. Yes, for rhubarb, corn, potatoes, carrots and some beans or peas, use 12 inch single pots. Other crops like tomatoes, cucumbers, some peas and beans, cauliflower, broccoli, silver beet, squash, cabbages, zucchini or similar sized plants, use the 10" pots. For smaller crops like lettuce, herbs, spinach, etc. use the Window Box. All these are just guides, you may find a better combination for your situation.
For pumpkins and the like, I prefer to grow them in large grow bags with a dripper serving 3 to 5 plants.
8. CapPlus tables, as mentioned are better using plain water. If your rainwater tank is higher than the table by 3 feet, you can just tap it directly to the tank without any pumping or pressure valve. If not, it is better and cheaper to use a 100 to 200 L tank to feed each table. Not much pressure is needed so long as there is a head of 2 to 3 feet it will work fine.
9. Yakon, can be grown in the 12" pot for this season and you will be able to get some harvest by the end of Autumn. You can also take cuttings to propagate, or use the old stumps which will regenerate next spring. Increase the number of plants to 10 and plant them planted in a large grow bag to be fed by a Smart-Dripper.
10. Your water logistics. 4x 22,000L = 88,000 L
- if you wish to use that amount of water over the next 12 months, you will have an average water availability of 240 L per day. As a rule of thumb, a large tomato plant or similar crop requires 1 L a day. If you allow that, you can probably allocate 100 plants (50 units of Hydrotray Double 10" modules, Hydrotray Single 12" units and Window Boxes) for veggies. For the Smart-Drippers, with a drip rate say of 10L per dripper per day, you can afford a water allocation up to a max of 14 drippers. These are just guides and you can adjust the crop mix as suggested above.
Hope I have answered your questions adequately.