Does my mix sound ok? First time indoor SIP gardener

[Ray Payne]

This will be my first try and I hope I have read and learned enough to put together a reasonably healty organic mix for my sub-irrigated indoor (my sunroom) vegetable garden.  I have for now been using grow lights to start my seedlings, and they are looking good but have only been exposed to coir and a tiny bit of liquid fish fertilizer.

Anyway, I transplanting them soon into the big containers and I bought peat moss, perlite, and I just picked up some Natures Helper Organic Soil Conditioner at the Co op.  This conditioner is 50% pine fines and 50% organic compost.

I plan on mixing it 42.8% Peat Moss, 42.8% Soil Conditioner, and 14.28% Perlite.   I'll use a 5 gal pail to measure the mixture, that's 3 Peat Moss, 3 Conditioner, and 1 perlite. Does that sound like it should work ok?   I do have a small bag of Jobes Vegetable & Tomato Organic Fertilizer I could ad in if ya'll think I should.  Would sure appreciate comments.   

[John F. Houpt II, PhD]

The mix sounds like it will hold the moisture and provide a good firm base for the roots. Since you didn't indicate what you are going to grow, I'm not sure about the nutrients.  My thoughts are to err on the side of more nutrients than less in my containers. I add about a cup of  the Jobes fertilizer spread out over the mix in the middle of the box and then a layer or two above that in my potting mix as I fill the containers. That way I have nutrients for the plant as the roots push downwards.  Dont' forget to add calicum to your mix for your tomato plants. I didn't last year and ended up with tip rot. So I poured soured raw milk onto the soil. This year I'm saving a couple of dozen egg shells, drying them and then crush them up adding to the soil mix in all of my containers.  I posted a Container Gardening 101 that might be useful. Please let us know how your garden works out, maybe even write a 101 on your garden experiences. 

[Ray Payne]

Great, Thank you so much Dr. Houpt for your response.  I will be (attempting to grow) vegetables both my wife and I like and I'm 70 with no knowledge of gardening accept for helping my father-in-law hilling potatoes a couple times.

I will be trying tomatoes, cucumbers, lettuce, cabbage, peas, beans, potatoes, broccoli, peppers, carrots and celery for starters.  I have learned which of these veggies are compatible in the same container.

Honored to take your advise and so happy that you responded!

[Anne Radcliffe]

Hi Ray

You may find that you have to reduce the soil conditioner some in exchange for more peat moss, as organic compost can get muddy and heavy, or interfere with proper wicking from the reservoir. I'd make peat moss the heaviest part of the balance when using a conditioner that's 50% compost, possibly as much as 70% of the final mix and balance with a little dolomite lime.

I have a self-built 6' SIP and I opted for a mixture that was sterile - 80% peat moss, about 15% perlite and 5%ish Vermiculite that was sown heavily with a slow-release organic fertilizer. The plants did quite excellently in this mix with a regular feeding. You can buy this mixture by the bale at garden centres as "pro mix" or you can make it yourself, but if you do make it yourself you'll have to add some dolomite lime to balance the pH of the peat moss. 

Only downside, plants will have to have firm support, because a high peat mix is gritty and loose.

Anne

[Ray Payne]

Thank You Anne.  Makes sense to go lighter on the soil conditioner and a make up for it on the Sphagnum Peat Moss because the soil conditioner was not 100% pine fines, but I've bought it, so I'll go ahead and it.  Trying to stay away from Vermiculite.  Thanks for the info about using the conditioner!

[John F. Houpt II, PhD]

Good take on the weight and wicking aspect Anne.  I didn't think about that when I read Ray's note. Sorry Ray!!!!  I used a potting mix and not potting solil for pretty much the same reasons as you mentioned and didn't link the two together.  Ray, here is the garden plan I used last year with very good success. Actually, I ended up having a junge of tomato vines, peppers and just about everything else you can imagine when I was done!! The birds loved it and defintely kept the insect population down to a dull roar! Did lose the cabbage to the cabbage worm.  Just something to look over and play with. John

[Ray Payne]

Thanks once again, you both are such a blessing and truly a great help!  I will have to follow up after my first crops and let you know.  I don't plan on taking most of my plants out onto the deck because my sunroom gets nearly 100% of all sun after about noon till sunset.  The sunroom is 8 feet of  glass all around with 5 feet of it being sliding with screens accept for two 8 foot sliding glass doors with screens leading to the deck (more of a greenhouse than a sunroom accept for the solid ceiling).   On cloudy days, I might use my two four bulb special grow lights if I think they'll need it.   I have a ceiling fan in the sunroom to help with circulation and assist in keeping the sunroom from getting too hot.  I also have a thru the wall heat pump if I need more cooling.  Wish me luck!

[Anne Radcliffe]

No worries, John! You are right, for a regular container mix, you want something that holds water a little bit better, and I defer to your expertise on that, since all my ordinary container plants tend to die ;) And you're right too about a heavier mix being better for supporting the roots of the plants.

SIPs with gritty mix are more like hydroponics and larger plants like tomatoes and peppers grown in them require a solid support system like a tripod stake or something braced, so keep this in mind otherwise your tomatoes may fall over as they're ready to fruit :)

Good luck, Ray! It sounds like you get a great deal of sun in that room. Keep an eye on the soil temperature. You may also want/need to mulch the top layer of mix after your plants come up a bit to protect the shallow-rooted plants, so their roots don't get overheated and the upper layer of soil doesn't dry out too quickly.

[Ray Payne]

Wow, Thanks Anne, I didn't even think about plants falling over!  Great heads up and darn good advice :-).  Going to try a mix of 4x5 gal pails of Peat, 1x5 gal pail of perlite and 1 five gal pail of the soil conditioner.  I'll also do the 2 cups or so of Jobes Organic Vegetable & Tomato Fertilizer as John suggested, and I save up some organic egg shells to mix in.  I think I'll maybe need to also add some dolomite lime to the container with the tomatoes.  Will watch the pH levels closely as well as the soil temperature to make sure my roots don't get overheated - lots to learn here - lol - maybe will keep me young :-)

[Anne Radcliffe]

You sound like you're well on track. :) I'm sure you'll do great. :D Keep us posted.