Estimate fertilzer needs by observation?

[Vanisle_BC]

I don't have my soil tested because I'm remote from testing facilities and my several beds contain soils with different characteristics & in different conditions.

My question is, what advice/experience/knowledge is available on deciding - simply by observation of soil and plant performance - what fertilizers or conditioners may need to be added?

If, for example, my cauliflower grows huge but doesn't flower do I have too little P or K and too much N (and is too much nitrogen really possible? I've read that most garden soils already have all the P & K they need; then again where gardening's concerned one can read all sorts of contradictory statements.)

Who on here doesn't use soil tests; how do they go about fertilizing (I mean vegetable gardens not farms ).

[jal_ut]

(I mean vegetable gardens not farms ).

Are you gardening in containers or out in the soil on your lot? If containers, all I can say is good luck.

If you are gardening out back in the soil on your lot, I can suggest that you go to the farm store and get a package of fertilizer that says NPK and use it according to the directions on the package.

Soils vary a lot from place to place. Is there a university near with an extension service? If so they will have good information. Local farm supply store near? Check with them.

Here a light dusting of Ammoniun Nitrate pellets gets the job done for most crops. The P&K seem to be abundant but Nitrogen is lacking.

You need to learn about your soil type and general needs. Good luck.

[Vanisle_BC]

James, Thanks for your reply.

I have ~18" high raised beds with soil from various sources plus ground-level beds in the existing "dirt". That dirt is also quite variable. We're on a rural-residential 3/4 acre that hadn't been virgin ground for decades before it became ours. We have everything from clayey material to improved/imported? soil to thin topsoil over rubble fill. Underlying most of it is a fine grained red hardpan I'd class as silt although that's an unscientific guess. It packs hard but is not sticky.

I favour 'organic' as opposed to 'chemical' fertiliser. I've used mostly a mix of seed, bone & kelp meals with a bit of lime. Application has been a bit spotty and so are my results. I grow mostly heritage or open-pollinated varieties and like to save seed. Tomatoes, lettuce do well. Broccoli not bad but cauliflower and root veggies not so good. Often a row of plants produces one or two good ones interspersed with runts.

"A package of NPK?" Do you mean "balanced" NPK? I'm looking for more specific information about modifying the soil based on watchng plant vigour and behaviour. More like empirical folk knowledge than scientific analysis or commercial advice.

[digitS']

I've been gardening in the same valley for over 45 years ... probably, a half dozen of those were non-gardening years ... There was a number of locations but they have been within about 30 miles of one another. The valley soil has all been moved by glacier activity a few thousand years ago. It's a real jumble of material from the Rockies.

I had my soil tested once and the advice from the agency was simply to add nitrogen. It seemed like cheap advice but my reading of ag information about the valley soil make-up since, pretty much confirmed that advice. Minerals are available in considerable amounts. pH can be a problem but I soon became mostly an organic gardener and plant material/compost tends to balance and reduce the high pH as well as providing plant nutrients.

My garden plants represent a good number of species with differing requirements. Generally speaking, it's a little hard to speak generally . However, most plant growth has a real need for N. I try to provide it with organic fertilizers -- expensive but I hope that they will be available for more than one year.

I should say that except in a small area in my backyard probably receiving almost too much compost and with all these years scratching around in a garden, I have utilized only one piece of ground for more than 10 years. Perhaps my gardening techniques would lead to depletion over a long-run. We should, at least, give that some thought even if we aren't bequeathing farmland to our grandchildren. IMO: Someone may be trying to grow things in our gardening ground in future decades and we shouldn't be messing things up for them.

Limited N may be detected in plants with a pale green colour. I realize that might indicate other problems like a magnesium deficiency, for example. However, I suspect the simpler soil tests won't show you Mg needed, either. You might test some things like calcium, sulfur, potash, Epsom salt (Mg). I did that with Epsom salt and wood ash. If anything, where I did not use it, plants grew better than where I had applied it. Oops! Anyway, that's where I garden.

Steve
here is a description of plants with mineral deficiencies from the University of Missouri: link

[Gary350]

You need to know what fertilizer plants need more than what fertilizer soil needs. I have not had my soil tested in 40 years.

Tomatoes need very low nitrogen other wise you get large plants with few tomatoes. Good NPK fertilizer for tomatoes is 4-4-10 plus calcium.

Corn likes nitrogen since ammonium nitrate is now illegal to sell you need to buy sodium nitrate or Urea. Urea is a nitrogen that no plants can use it needs calcium to convert to a type of nitrogen plants can use.

Beans take nitrogen from the air but they can use 15-15-15- fertilizer too.

Tomatoes, peppers, melons, squash all need calcium for BER = blossom end rot.

Potatoes need low nitrogen & high potassium.

Feed your plants, not your soil.

[jal_ut]

""A package of NPK?" Do you mean "balanced" NPK? I'm looking for more specific information about modifying the soil based on watchng plant vigour and behaviour. More like empirical folk knowledge than scientific analysis or commercial advice."

When you look at fertilizers in the store in their containers, they will have a designation such as 16-8-10. Those numbers represent the parts of Nitrogen, Phosphorous and Potassium in the product. Yes, you can apply a bit of this to your soil and "watch" the plants vigor perk up. You want to see a difference? Only fertilize every other pot or plot so you have a comparison. Experiment and learn.

[jal_ut]

I might add, only put fertilizer on the soil, never on the plant itself as the fertilizers can burn the plant if put on the leaves. And don't overdo it as too much will draw the water out of the plants and they wilt and die. A little goes a long way. Experiment and learn.

[Vanisle_BC]

Steve, Thanks for the U. of Missouri link. I'm still digesting the info to see what might be relevant to my own garden.

I don't use so-called 'chemical' fertilizers or bags of 'NPK.' I prefer to stick with 'organics' that are said to be more friendly to organisms and general health of the soil. It's not something I would argue over, just the choice I make.

I don't suspect a shortage of nitrogen, because my coles are big and vigorous with dark green leaves. But all are slow or even unwilling to make heads. Also although they have thick, sturdy-looking stems they tend to need staking: Lower parts of the stems grow along the ground before curving upward, leaning somewhat.

Root crops and onions seldom do as well as I think they should (thank goodness for garlic that never fails!)

My suspicion is a lack of phosphorous and/or potassium in the soil (that's where my plants get their nutrients from ). Maybe the curved/leaning stems signify poor root development? Does the failure to head up mean I need to add something to promote 'flowering'?

I've tried DIY soil test kits but the results were hard to interpret and quite inconsistent. I subsequently read some opinions that those kits are not really useful.

[jal_ut]

"I'm looking for more specific information about modifying the soil based on watchng plant vigour and behaviour. More like empirical folk knowledge than scientific analysis or commercial advice."

Well I have only been gardening for 70 + years. What the hell could I know about it? Have fun.

[imafan26]

There are signs that plants give that will tell you if you have some deficiencies, but some deficiencies are actually caused not by absolute lack of the nutrient or mineral in the soil, but because of their availability. pH and other elements present in high amounts can affect the availability of other elements

If plants are small and otherwise healthy it is usually because you are using organic fertilizer in a relatively new garden that is less than 3 years old. Nitrogen is the hardest element to obtain in quantity organically without supplements.

Undersized plants, pale green and older leaves yellowing (progressing to more yellowing as deficiency worsens) are signs of nitrogen deficiency.

Too much nitrogen on the other hand produces large lush growth at the expense of root growth in bulbing plants and the productions of additional shoots and growth at the expense of fruiting and flowering

Phosphorus deficiency is easy to see on small seedlings as phosphorus is needed in larger quantities to fuel plant growth. This you will notice as purplish stems and leaves. (It is common in tomato seedlings (heavy feeder) that have been left in small pots for too long. it improves rapidly when transplanted into the proper enriched soil or with fertilizer.

Chlorosis has many causes. Most of them are micronutrients with iron being the most common. Where the chlorosis occurs like interveinal or around the leaf margins will be clues to what deficiency causes it.
Iron and zinc deficiencies may actually be caused by too much phosphorus

Adding too much fertilizer can be as detrimental and more harmful to the environment as too little.

The only real way that I know of to test if you have too much or too little of a nutrient is to experiment and grow a crop and see how it does. Just because it is growing well and looks good does not mean you don't have excess fertilizer. Some nutrients like nitrogen are volatile and mobile. What is not used by the plant will be either denitrified and return to the air or be leached away into the water table and eventually into streams lakes and oceans where it can cause other problems when levels are high. Some elements like phosphorus, can hang around a long time. While it will also leach, it can take years to bring high levels down to a normal range. In the meantime phosphorus and alkaline condition may bind other elements so badly that they are not easily available to plants.

https://customers.hbci.com/~wenonah/min-def/list.htm
https://landresources.montana.edu/nm/documents/NM9.pdf
https://counties.agrilife.org/valverde/f ... Suffer.pdf
https://www.cropnutrition.com/nutrient-knowledge

[applestar]

OK I haven’t pitched in because I’m not very sure of what I think I know. But I feel like sharing my ignorance today, so I will

- I agree that lush dark growth probably means nitrogen is OK.
- leaning and sideways stem in brassica like cauliflower to me means you need to hill the base — support base of plant with more soil (as well as plant transplants deeper - but I think you said you grow yours direct seed) Brassica stem between seed leaves and true leaves is thinner than upper stem and seedlings/plants tend to flop over. It’s OK to “stake” them by sliding 2-3 thin bamboo canes in strategic leaf crotches.
- you say tomatoes and broccoli grow well, but I’m still wondering if the cauliflowers are not getting enough light or heat? Tomatoes grow taller so can grow into sunnier height, and cauliflower generally needs more heat than broccoli. I think of cauliflower as plant one week later than broccoli... but in my garden, the short spring/sudden summer makes it difficult to get the timing right.

- which root crops do not grow well? I have trouble with radishes and beets( as well as spinach and Swiss chard) and have concluded my soil pH is too low for them, though not necessarily that more calcium is needed. Part of this conclusion is based on what WEEDS grow well (wood sorrel, sheep sorrel, yellow dock, buttercups... strawberries are spreading everywhere.). I have been thinking of trying the wood ash trick — I just don’t have the chance to burn wood to make ash very often.

- I’m thinking garlic is a bit like onions and need the nitrogen. They also probably do well where winter is milder and they have more opportunity to establish roots, plus you have the longer days in the summer, too.

- You said root growths are good? A part of my garden had clubroot — this was a good while back, maybe just after I joined the forum. It took a while for the garden to recover from that, though I have garden beds scattered around the property so I was able to grow brassicas in other beds, and I guess walking on the lawn in between beds meant I wasn’t spreading the disease too readily. The clubroot was discovered on my rutabagas — the tops grew huge, but the roots were gnarled and never developed except for I think 2 good ones and 1 runty one. I’ve been trying to get back to growing rutabagas ever since.

[Vanisle_BC]

Applestar, thanks . I can't respond properly right now - out of town ophthalmologist plus dental appointments and a computer problem that involves a running battle with Dell; woodshed needs propped up and firewood stacked, yard's full of fallen leaves; gutters full of pine needles with much rain in the forecast - whine, whine. But I'm thinking of wood ashes too. I'll respond more fully, later .

[applestar]

Know what you mean — I originally posted from the iPhone and I’ve had to correct a few glaring mistakes and typos I didn’t notice and was too frustrated to check more fully. So it’s a good thing you’ll be coming back to respond later.

[Vanisle_BC]

Got my eye lasered today and the 'wrong' lapop is on its way back for a refund so I'm feeling a bit more sociable.

Applestar, I like your 'not very sure of what I think I know' approach to this subject. I feel the same way about many things, especially gardening.

My cauliflower, cabbage & broccoli are all very large & lush but mostly headless. So we agree there's likely no lack of nitrogen.

As for depth of transplant I've been inconsistent (it's my style ). Seed starts have been in either soil blocks or cells/pots but I think you're right in suspecting planting depth could have been greater. I wonder how deep would be too deep; and I'm probably inconsistent - again - in the stage of growth at which I set them in the ground.

Onions & garlic do reasonably well for me; maybe as you say because they get plenty of nitrogen.

Like you I've had poor beets, turnip, radishes, spinach; but vigorous strawbewrries and buttercups that leave no opportunity untapped. Ph is one test I could do myself with a garden-store kit although in the past I've been unsure of its accuracy. I'll try again.

I'm familiar with puny, runty-rooted rutabaga but this year I switched from Marian to Laurentian with much better results. In fact most of my root crops were a bit better this year, which I credit to the addition of more bone meal than usual.

I hope you get back to growing rutabaga. We like it boiled & mashed with pepper. A robust flavour! Where I grew up they were called neeps or tumshies. They're traditional with haggis. I don't recall ever seeing those effete little turnips at the grocery store, no bigger than a tennis ball .

I've been saving wood ashes. This time around I'm going to put a lot more 'feeding' into the soil; commercial composted chick manure, my own high-N compost (made with much grass), ashes, lime and still more bone meal. I feel I have to overcome a preponderance of nitrogen but I'll be "playing it by ear." My guess is that it's difficult to provide too much of any nutrient; rather too little of the others - ??

Thanks for your input to this discussion.

[dylansova96]

When I was having a problem with my soil I bought a fertilizer that someone in this forun sugested. It improved the retention of the water of my soil and it did some other stuff, specially because of the amount of potassium in the product. I think Amazon still selling it, it is something called Greensand and I know that the product comes from Brazil because I researched about it. Maybe you should check it out and tell us if it resolved your problem.

[Vanisle_BC]

Thanks Dylan. I've applied a little greensand before but it's pretty expensive in any quantity. I can get it from bulk bins near-locally. I liked the idea that its granularity might improve the texture & drainage of clay-ey soil as well as adding potassium. I probably didn't use enough of it to make much difference.

Are we talking the same stuff? What I got was a grey, very fine-grained sand.