Garden Fertilizer Tips – How And When To Fertilize

Garden Fertilizer Tips From The Sun

Today I continue with the garden fertilizer tips.

Last week, I outlined a basic fertilizer schedule and received a couple of comments from people who disagreed with my suggestions, so I thought I’d address their concerns here in more detail.

I always appreciate any feedback people have to give, even when it runs counter to my advice. Some great learning opportunities come when we have these discussions.

Garden Fertilizer Tips – My Answers

Various comments are in italics below.

Comment: Lime is not a good idea! Many of us have alkaline soil to begin with! My dad once took the recommendation of his buddies and applied lime to my mother’s vegetable garden (it was the only thing he did in the garden since turning up the sod). That great little veggie patch turned into an unproductive wasteland. A rule that is generally used for pruning should be used for fertilizers, too: if you don’t know why you are doing it… DON’T.

Phil: That is an excellent rule. The soil is a fragile environment and we can cause real damage by using the wrong materials. One of the important garden fertilizer tips I often repeat is to avoid using mineral fertilizers without a soil test – except calcitic lime, which is calcium carbonate. I absolutely do not recommend dolomite lime – that’s where the problems come in. And I don’t recommend a big application of calcitic lime without doing a soil test first – only 10 pounds per 1000 square feet, not 50-200 pounds as the labels recommend. Actually, even one of my favorite organic soil labs – Crop Services International – has recommended 50 pounds without a soil test. But I stick with 10 pounds, which is just a light dusting that you’ll barely be able to see after doing it. Probably at least 95% of soils will benefit from this. Also, calcium does not necessarily increase alkalinity.

No, Calcium does increase alkalinity.

You’re right that calcium does usually increase pH, but on high pH soils, it sometimes lowers pH, generally when the high pH is due to nutrients other than calcium, such as magnesium or potassium – it just goes to show that soil is a mysterious environment.

Spraying the leaves is another NO NO. Plants transpire 24 hours a day. When you spray crap on the leaves you are force feeding the plants. Not a good idea!

I’ve never come across any negatives to foliar feeding other than the fact that occasionally the benefits are negligible. All of my favorite ecological farming consultants are recommending it as one of the most important garden fertilizer tips for improving crop nutrition.

Plants are a little like us – we eat some foods even if we don’t need them. Plants are the same – they will uptake good and bad.

Actually, they can choose what they need of some nutrients, but it’s true, for others they will take all they can get. That’s why our goal is to spray just tiny amounts of a broad spectrum of beneficial nutrients in their natural form (e.g. sea minerals and kelp), and we stay away from toxins.

Plants never uptake nutrients at night. At night they only uptake water. If you must feed plants – and I do say if you must – ONLY feed plants in the morning.

Plants do take up nutrients at night – foliar fertilizing in the evening can be very useful. But yes, I like morning fertilizing, too, and that’s when I often tend to do it.

As they say in all bird sanctuaries, don’t feed the birds, because it is not good for them. The same applies to ALL plant life.

I don’t like seeing people feeding foods like bread to birds, either, but that’s because we know this causes problems. It’s true that even bird feeders have some downsides. But with a garden, especially a vegetable garden, we’re trying to grow food plants that probably wouldn’t grow there otherwise, and we’re often doing it on very degraded soils. If we want those plants to be pest free, and if our goal is growing nutrient dense food, we often need to help out a little bit by supplementing nutrients, organic matter, microorganisms and water.

If you set up your garden properly you don’t need all the other bits of rubbish from the shops. We only started using all this rubbish in the last 60 odd years or so. The soil food web has been on the decline ever since.

I agree, chemical use has drastically increased in the last 60 years, threatening the entire planet. But using materials like fish, kelp and rock dust as organic fertilizers has been done for centuries, even millenia. Now we’re lucky that we can get them in a bottle (although there are potential sustainability issues with some of this, too). I agree that we want to use external inputs as little as possible, and I agree that it can be possible to grow a successful organic garden without them. But using a few of them, especially early on in a garden’s life, is often very helpful to speed up the process of soil balancing that nature would otherwise take hundreds of years to accomplish. It helps us to quickly get the nutrient-density back into our vegetables that we so desperately need.

Do you have a sources page where this “good research” is. I am using your website as a starting point for my thesis research into soil amendments and sustainable agriculture (this was in response to my statement, “there is good research showing that using organic fertilizers more often, in lower doses (often extremely low doses), promotes the best results.”

One of my favorites is Roland Bunch’s summary of some of the work by Brazilian soil scientist Ana Primavesi: Nutrient Quantity vs. Nutrient Access. Everyone should download this for reading on a rainy day.

Any questions about these garden fertilizer tips or other fertilizing methods? Feel free to ask below.

11 Comments

  1. Djejenkins on April 21, 2012 at 5:02 pm

    I have a question: Most bags of compost and manure say they have about .1-.1-.1 of the big 3, I have tested my own compost and it is somewhat higher but still not in the 10-10-10 range recommended for most plants. So, how do you get enough without using fertilizers? Is 10-10-10 the same as .1-.1-.1? Am I missing something?

    • Phil on April 24, 2012 at 4:52 pm

      Good question. It requires a longer answer, so perhaps I’ll blog about it this week. The short answer is that 10-10-10 is not recommended for plants – it’s recommended for the profits of the manufacturers. Plant nutrition is much more complex than 10-10-10. But to answer this in more detail, I’ll write a full post. Compost is indeed the best “fertilizer” available (if it’s good compost).

  2. Lynne on April 21, 2012 at 9:58 pm

    Correct me if I’m wrong, Phil. While soil scientists may recommend foliar feeding, every horticulturalist I’ve consulted agrees that only minimal nutrients are absorbed by leaves. Photosynthesis occurs in the leaves, but the conversion of nutrients into plant-usable forms occurs in the roots. The nutrients are transported back to the plant stems and roots, mostly in the water that is taken up. 

    • Lynne on April 21, 2012 at 9:59 pm

      Sorry, I meant nutrients are transported to the stems and LEAVES. Duh.

      • Phil on April 24, 2012 at 5:06 pm

        Hi Lynne, good point – most horticulturalists are coming out of a more conventional approach to gardening. They think differently about a lot of things, and the foliar feeding research isn’t part of the mainstream curriculum yet. But leaves absolutely do absorb most if not all nutrients. Some are translocated throughout the plant better than others, though – some mostly stay in the leaf. And it’s true that foliar feeding is not a magic bullet – it’s more like icing on the cake. Good soil management is still the most important.

  3. Shmooglepuss on May 22, 2012 at 10:37 am

    Hi there,Thanks for providing this plethora of useful info, I could spend an entire day on your site!I’ve got a question about fertilizing. I started plants from seed for the first time this year in late March and early April, under grow lights in the basement. They are almost all in a small plastic greenhouse outside now (I’m in P.E.I, Canada) and I’ve fed them nothing but seaweed tea. I fill a bucket with seaweed off the shore, top it up with water, strain it three days later and further dilute that mix with a little more water. I have to admit, I am truly amazed at how well the plants are growing. They’re a vivid green, with healthy, strong stems and the zucchini are actually starting to produce fruit in their cardboard milk containers. A few tomato plants are starting to flower as well (still in their peat pots). I’m wondering though, if there is something I should be adding to the “brew” of seaweed tea at some point after the plants have been transplanted to the beds, to boost the nitrogen level? Grass clippings perhaps?They’ll be going into soil that is less than ideal. The beds are filled with topsoil and will have composted sheep manure added. Would very much appreciate any advice. Thanks again for providing this site!-Lissa

    • Phil on May 24, 2012 at 8:10 pm

      Hi Lissa (or Lisa?), sounds like you’re already on the right track. Your composted manure will probably provide the nitrogen you need. Grass clippings are best in a compost pile. They can be used as part of the mulch, but not too much or they get slimy and anaerobic.If you can catch fish, putting a fish or part of a fish underneath each plant during planting is another great way to get nitrogen and other minerals. Also, watering with sea water a couple of times a year can be very helpful for getting a broad range of nutrients. You can use as much as 1 cup per square foot of soil.Good luck this year!

      • Shmooglepuss on May 25, 2012 at 6:33 pm

        Thanks so much for the advice. A watering with sea water will be a snap, we’re right on a cove connected to the Northumberland Strait. No shortage of fish around here either, and the free fertilizer washes up on our backyard daily. Who knew living by the ocean could be so helpful in the garden? Thanks again,-Lissa -spelling correct 🙂

  4. Camille Geurrier on May 14, 2015 at 11:03 pm

    Thank you for sharing how to effectively fertilize your garden. I have never seriously started a garden, but I have always wanted one. I work hard in my yard to make it look good. I do what I can to make the grass green but sometimes it is hard to get that nice, soft, green grass that every one wants. Like you said, plants take up nutrients at night, but most people like morning fertilizing better. Thanks for sharing!-Camille

  5. Megan Earl on July 19, 2016 at 2:29 pm

    I recently bought a house with a huge garden and I want to make sure I take good care of it. Unfortunately, I’m not an expert on gardens or fertilizer or anything like that! It’s good to know that fertilizing in the morning is okay! That’s the only time I’m able to work on my garden. Thanks for sharing!

  6. Sarah Smith on November 17, 2016 at 8:35 pm

    I want to help my garden and fertilize it correctly. I had no idea that you should never spray things on the plant’s leaves as it essential force feeds the plants. Another thing to do is to invest in organic nutrients for the plants so that you can be sure you won’t damage it.

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