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Cake day: March 26th, 2025

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  • We can go back and forth on this all day, but I’m gonna just sum my point into a nice tight thesis: broadcast application of phosphorus is by far the biggest issue in terms of runoff (as you allude to re: lawn fertilizer). Home gardening use of phosphorus mixed into soil is entirely harmless by comparison.

    I agree excess potassium is bad. Doesn’t happen overnight.

    Plenty of reputable books and horticulturalists recommend even-ratio’d ferts for all these crops. My local ag office explicitly recommends 10-10-10 in particular for tomatoes year-round in a home garden context. It’s simplified, suboptimal advice; we’re on the same page there - but not malpractice.


  • Phosphate - Excess phosphate is water soluable and runs off like nitrate. This causes all sorts of issues in waterways.

    Not at all true for the purposes of home gardening: https://extension.missouri.edu/publications/g9181. Granular fertilizer worked into the soil and covered by mulch isn’t going anywhere.

    There is little potential for phosphorus to leach through soil into groundwater. Soil particles have a large capacity to fix phosphorus in forms that are immobile in soil.

    Only 1/3 of it is immediately available. The other 2/3rd are insoluable and stays in the soil for months. It then releases over the winter and early spring and runs off into the waterways.

    Entirely depends on the form of phosphate. See “Table 1: Percentages of water-soluble and available phosphate in several common fertilizer source”. The runoff bit is still nonsense.

    https://extension.umn.edu/phosphorus-and-potassium/understanding-phosphorus-fertilizers#materials-619210

    Potassium - elevated levels of potassium in some species is an issue in others it’s not a problem. For example corn and other grasses will suck up extra K+ and store it. Howeve in tomatoes, peppers, potatoes etc it can inhibit the uptake of Ca+ and Mg+.

    Sure - that buildup takes a while though.

    The idea that hitting plants with 3-1-2 fertilizer causes top heavy growth is myth that is passed around gardening forums and many books To put it bluntly it flat out doesn’t happen. The root/shoot ratio is quite a bit more complex than that.

    I agree that it’s more complex than that, and early 3-1-2 is in no way a catastrophic death knell, but there’s a grain of truth to it. As I think we also agree, pretty much every reputable source will tell you to prep the bed with a higher P+K feed in the early season.



  • Throwing out clarification since I think I was the one who threw out the even-ratio’d fert suggestion to you: your read is spot on.

    The_v has a totally valid point here, but is substantially overstating the issue. Most plants do prefer an overall ratio closer to 3-1-2 over their lifetime, so if you feed them 10-10-10 endlessly, you’ll eventually get toxic build-up of phosphorus and potassium. Unless your starting soil is abnormally high in those already, that will take at least a few years to manifest, and can be easily addressed by switching to nitrogen-heavy feed until your plants take up the excess P+K.

    Additionally, you don’t want to hit the plants with a higher-N 3-1-2 feed right out the gate - especially in hotter climates - since that can cause top-heavy growth with too much foliage but not a big enough root system to feed those leaves. That’s why many people add bone meal when planting or prep the bed with a higher P+K feed in the early season.

    You won’t have any downside sticking with the 10-10-10 for a while; just don’t do it for years on end without getting your soil tested.












    • I don’t want to spoil your fun with the mint, but the runners above ground aren’t the ones to worry about. Mint likes to spread through its roots… a lot. Best kept in a container ;).
    • Most pests are visible to the eye, but there are a few exceptions like spider mites. You’ll typically know you have them by other obvious signs though. A loupe can be helpful for insect ID, but isn’t crucial.
    • You can mostly ignore the nutrition from that compost. You’d have to do some math to know the impact of that fertilized garden soil, but it’s likely quite modest. Feel free to use 1/2 - 3/4 the recommended amount of granular for the first month or two if you want to be conservative.
    • High NPK numbers aren’t necessarily good or bad, but they are more concentrated and can be more liable to burn things, depending on their form factor and nutrient release pattern.
    • As for lettuce/onion seedlings, ideally you till some fertilizer into the bed while you’re prepping it. You could give them some liquid fertilizer at half-strength to make up the difference - but yeah, they’ll still do fine if you just sidedress in a couple of weeks. Both those plants really like higher-nitrogen feeds, so you might want to think about getting a different fertilizer for them down the road.

    All that being said, don’t feel obliged to follow any of this if you don’t want to. You’ve definitely set yourself up to get something edible and tasty, so don’t sweat the details if it starts getting in the way of your fun. Hope it helps and happy gardening!


  • dgdft@lemmy.worldOPtoGardening@lemmy.worldLate April Garden
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    13 days ago

    Thanks! I’m in central Texas - zone 8.

    My wife and I are talking about moving up north towards the end of the summer, so I’ve been trying to make the most of this last season. I’ll definitely miss the early start of spring, but I’m excited to try out new local plants wherever we end up. Having to hunt for plants that can deal with weeks of >100F days and no rain gets old after a while.



  • dgdft@lemmy.worldtoGardening@lemmy.worldFirst Time Gardening 2: Electric Bugaloo
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    14 days ago

    Great start OP! Some blunt honesty: it’s overcrowded to the point that you will not be getting optimal results - but you’ve set yourself up for some good learning experience nonetheless. Further guidance:

    • Get some balanced granular fertilizer (e.g. 5-5-5) and apply according to package instructions, mixing into the top 1-2 inches of soil beneath the mulch without injuring roots. Do not be afraid to use basic-ass Miracle-Gro or the like; organic ferts do not have magical properties that make them more effective than inorganic.
    • Don’t overtreat for pests: get a spraybottle of insecticidal soap for spot treatment of aphids and the like. Hand-pick larger bugs like hornworms. If you have a problem that the two above steps can’t solve, reach out to your ag extension office for ID help and further guidance. Eschew neem oil; it’s noob bait.
    • Figure out how you want to support those tomatoes. Premade storebought cages will suffice for this year, but you’ll want to make your own cages from wire panel (100x easier than it sounds) or set up a staking system eventually.
    • “Full sun” is a bit of a misnomer: in practice, it’s a shorthand term of art for 8+ hours of direct light. Fortunately, everything you planted will be happy with that 6-8 range. You’ll be sacrificing about a third of your max yield, but you’re spot on that it’ll make life much easier in the summer.
    • Planting mint in-ground is a home gardening rite of passage. You will learn from that. Welcome to the club ;).