Good question and it raises some additional questions many of us don't think about too often.

The first thing that occurs to me is how you will get all the needed soil up to the roof, assuming the roof will hold all that weight? And will it allow for proper water drainage without it showing up in the bedrooms below?

Personally I'd go with containers. More flexibility, can be filled below and hoisted up to the roof, and better control of drainage. Plus they lend themselves to easier crop rotation and to intensive planting and tend (at least here) to have less pest problems.

Then I'd want to know about the sun exposure - roof vs. yard? Is there lots of surrounding buildings that could shade the yard but not the roof? If so, roof wins.

Third, availability of good container mix there? Cost of it vs. digging up the ground. Plus keep in mind that container mix will have to be refreshed if not replaced every couple of years. Is compost and soil additives readily available at a reasonable cost? If not the in-ground wins out.

Then will you have family help constructing and caring for either? Good help is hard to find so be sure to get their opinions too first. IME it is easier to get family to help with containers than with the in-ground gardens but your folks may feel differently.

Just some thoughts to consider. Good luck with your plans. :)

Dave

PS: would I want my brother and sister-in-law living with me? Uhhhh, no. 6 years younger but only half our energy level and no interest in anything that doesn't include a couch and a big screen TV. :)

I agree with Dave on everything. You might want to look into the container gardening forum to get some ideas.
Also, can you do some of each? Roof-top for more shallow rooted plants and in-ground for other things that maybe need more space? Corn, tomatoes, squash to think of a few.
Whenever I stay in a big city, I check out the roof-top gardens! If I HAD to live in a city, I would certainly have one!
Also, you could look into community gardens for more space! Nancy

Thanks Dave and Nancy

Really appreciate your replies and it did help me in further evaluating the two scenarios

I will however based on your inputs reword my questions as follows:

1/ Considering all other things are perfect for both in ground as well as roof top gardening (including sunlight, compost, soil, potting mixes, etc. etc.), which option should I chose? Particularly when the help for my gardening activities is going to mainly come from the third brother wishing to move in (but then i will have no space for in ground garden)?

2/ Like Nancy said that shallow rooted plants can be had on roof top. But if I were to have raised bed type structure on my roof top like 15-18 inch deep, can I expect the results of the larger deep rooted plants to be close to in ground plantings?

And yes Dave, one more thing. With respect to your PS note, that is why I qualified my query with this statement "and you were indifferent over having your brother in or out of this setup" :)

Thanks again to both of you for your replies and time

Btw, community gardens are hard to find over here, unfortunately :(

I do both in-ground gardens and big containers. So I'd say for question #1) amount of production - in ground. For convenience and ease of care but with somewhat less production - rooftop containers.

#2 - Yes. While I can't go with an actual raised bed on my decking because of the weight, I can do deep very large containers (half barrels) so they have the depth advantages of a raised bed but are easier to care for and anything can grow well in them. The only restriction on amount of production is the size of the container you use.

Does that help?

Dave

Thanks Dave.

Yeah it certainly helps.

By somewhat less production can I assume 80:100 or similar close levels?

And also if you just re confirm that if I were to go for a bigger size container, I can come even closer to the 100 mark?

Thanks again.

Clearly since you do not have the space it will have to be roof top. You are in Zone 10. Rooftops get mighty hot here, there they will be super hot. You may be limited in what you can grow.

On the other hand, a well designed system will keep the house cool due to the shadow. But there is no getting around the fact that you will be limited in the amount of soil you have. A drip system, operated daily, is almost mandatory. I would consider a system of long cattle tanks, supported by horizontal steel beams which would discharge their weight on bearing walls. Those would not leak, and accommodate only limited soil, but one mistake in watering and you will lose your crop (this could be overcome by placing drains under the tanks, discharging onto the downspouts). Then there is also the matter of carrying mulch to the roof.

By somewhat less production can I assume 80:100 or similar close levels?

More like 70-75 % using even the largest containers.

But it will also depend to a degree on what vegetables you plant to grow and what varieties you choose. For example, most all leafy greens will be close to 100% in properly maintained, fed, and watered containers/raised beds (a raised bed is just a big container in many respects).

Squash, cukes, small melons and such will fall more in the 75% range I think. Corn. potatoes, indeterminate tomatoes, and other large plants will fall into the 50-60% ranges when compared to in-ground production.

But this is all based on many variables that can skew your results drastically. Some of them glib mentioned - your climate and the demands it will put on any garden is a big one and we can only speculate about it. Just as my methods and results can't compare to someone gardening in the US but in Minnesota or Idaho, my results just won't compare to yours with any validity since the climates are so different.

But in addition there is the simple fact that container gardening is so different from in-ground gardening. It is a different methodology, requires different expectations, VERY different feeding and watering regimens, different soils, etc. When one does both I find it requires a totally different mind-set when I move from one area to the other.

So no matter which route you go you will have a learning curve to go through. That's why I recommend keeping things as flexible, as open to future change, as possible.

Dave

Saood, I didn't even take into consideration your zone and where you are living as the others did! I would listen to them!!!! Nancy Good luck!

Thank you all for you valuable time and advise.
According to the USDA zone number Karachi may be falling in z9-10 according to the high-low calculations. But the extreme heat (between 100-115C) with High humidity is in the months between June - August (3 months). The monsoon rains also come during this time. Rest all the time its just perfectly fine. The non stop breeze keeps the temps in check.

I do have a roof top container gardening setup in the current place that I live and its going great.

100 -115 C ???? Not F???

:)

Yes yes, thats an F :)

We live in Karachi - Not the planet Mercury...

What you plant matters too. To get the most calories per sq ft, root crops like carrots, turnips, or potatoes are a must. Or, do you want to grow crops that would be expensive to buy often, like most herbs (at least in my area)?

Here is a link that might be useful: Grow Biointensive Method

This post was edited by DirtandYarn on Fri, Feb 14, 14 at 2:37

Yes, carrots in 110F will do very well⦠anyhow the most calories per square foot are sweet potatoes, and those do grow in 100F weather.

Carrots in 110F???? Potatoes in 100F? Have I read it correctly?

SO it sounds to me like depth of the containers, amount and price of soil and additives, amount of rain, and temperature...
also types of veggies...

are all key factors.
Personally, i would plant some fruit trees, if you can on the ground floor, but there are some you can container also, like dwarf papaya, but then i love papaya :)

Saood, my post was sarcastic. You can not do carrots nor potatoes in that sauna.

look on line for rain gutter grow system also on facebook. or bucket gardening on youtube. by a guy named larry hall. It is a self watering system and small space like square foot gardening. I plan to use it this year for some of my garden.

Thanks Veggievicki

This guy, Larry Hall, has some really cool stuff on his channel. Looks like a must try.

Thanks again.

The question with rain gutter schemes (narrow channels where the vegetables grow) is what happens when the temperature is 115F. Answer: in ground vegetables will have their roots at a much lower temperatures. Large containers should be able to buffer the temperature some, averaging with whatever cooling the following night provides. But gutters on a roof will go to 115F, pronto, because they have little thermal mass. I am not sure that there are many vegetable plants that like their roots that warm.

I grew strawberries and a handful of other things in a gutter thin film hydro system, on a south facing balcony in zone 8. Strawberries did great.

I also tried Larry Hall's bucket system, and it was mostly a failure. The bottom half of the buckets stayed too wet. Some stuff did well, but frankly I think I would have been better off using the buckets like standard pots.

Can you explain the working model of the gutter thin film hydro system. Is there any link you can share explaining it?

Thanks

Glib,

Perhaps the gutter system wont be operational during the 4 months of high heat. It would be for the remaining 8 months.

Btw, trying to thinking out of the box. The greenhouse is generally for cold weather but we can also have a greenhouse in place for such summer months and controlling the temps by Fans and / or Air conditioners. It might get expensive but have a look at the tomato prices in Karachi between these months and the winter months - i.e. Dec/Jan

In August they were Pak Rupees (PKR). 200 per kg (retail) and in Dec/Jan they were PKR 10 per kg. i.e. @ 5% of the summer prices and they say tomato is a warm season veggie :)

These number may make the greenhouse viable.

Maybe not the greenhouse, because it traps too much heat and you can grow 12 months a year even without heat. What you need is a transparent roof, perhaps even with gutters and a valve to send the water either in the sewer, or in the containers. There is no better water than rain water, so why waste it?

You mean transparent roof but not the side walls?
But how can the temps come down just by transparent roofs ?

To clarify, our roofs are not like those slanting ones usually found in US. We have concrete straight roofs.

I understand. If you want to protect your vegetables from the weather, you have to allow ventilation or the temperature will rise. Standard vents in standard greenhouses can not remove a lot of heat. Also, greenhouses breed a lot of plant diseases, again due to poor ventilation. Hoop houses in this country are often made with removable sides, to insure excellent ventilation.