Possibly pH or nutrient imbalances :)

You are right, it may be related to nutrient imbalance or pH imbalance.

In hydroponically grown rice seedlings, whitening of leaf tips is commonly caused by nutrient imbalances, especially a deficiency of nitrogen or zinc, both essential for healthy growth and chlorophyll production. If the nutrient solution's nitrogen level is too low (below 100 ppm) or zinc is insufficient, leaves can lose their green color from the tips. Another major factor is high salt concentration (EC > 2.0 dS/m) in the solution, which restricts water absorption and leads to tip burn. Additionally, an incorrect pH level outside the 5.5-6.5 range can block nutrient uptake, especially micronutrients like zinc and iron, causing whitening. Excessive light or high temperatures above 35°C may also stress the plants, leading to bleaching of tender leaf tips. To prevent this, regularly check and adjust the nutrient composition, maintain EC between 1.5-2.0 dS/m, keep pH optimal, and ensure appropriate light and temperature conditions.

Apart from nutrient or pH imbalance, whitening of leaf tips in rice can also be caused by the white tip nematode, Aphelenchoides besseyi. This microscopic worm attacks the growing tips of the plant, leading to silvery or white discoloration of leaf tips, along with twisting and crinkling of leaves. The nematode survives in dry seeds and becomes active during germination, spreading through infected seeds or water. Although rare in hydroponics, contaminated seeds can introduce this nematode, causing similar whitening symptoms. To prevent this, always use nematode-free seeds or treat seeds with hot water at 52-55°C for 15 minutes before sowing. After germination, if white tip nematode infection is detected in rice seedlings, immediate removal of infected plants (rogueing) can help limit the spread. Strengthening plant nutrition, especially with potassium, can reduce damage severity. Applying bio-nematicides like Paecilomyces lilacinus may suppress nematode activity.

I hope you’ve got some idea about this now.

Glad I could help...

Nutrient deficinecy...

May be iron... specifically

A shortage of nitrogen usually causes more pallor over the whole plant, but especially on the older leaves, (since N is moved from the older leaves to keep the younger leaves alive). Old leaves thus senesce, (die off), unusually early in plants that are short on N. I don't think a shortage of N explains the symptoms on your rice. Nor does a shortage of zinc - from memory, a shortage of Zn shows mainly in the younger leaves, and does not typically cause scorched tips, (symptoms of zinc shortage include laxness, and small leaves). The scorched leaf tips that can be seen in your picture are more like what you see in plants that are struggling with salt; checking the EC of your nutrient solution would thus be a good place to start. Scorched leaf tips can also be caused by other stresses, such as heat. I mainly grow temperate rice varieties, and I find that when grown indoors they suffer when temperatures get above about 35C for long, (depending on other conditions, like humidity and light intensity), so it might be good to hang a thermometer near your plants in the middle of the day, and check the temperature that they are exposed to then.

1. Nutrient Deficiencies

• Zinc Deficiency: Common in rice fields, especially in early growth stages. Symptoms: White or yellowish tips, stunted growth, bronzing of older leaves. Solution: Apply zinc sulfate (ZnSO₄) at 25–50 kg/ha (with organic matter for better efficiency).
• Nitrogen Deficiency: May cause tip whitening followed by yellowing. Solution: Apply urea or other nitrogen sources based on soil test.

2. Water Stress

• Too much or too little water can affect nutrient uptake and cause tip whitening. Over-irrigation: Leads to leaching of nutrients like Zn, Fe. Under-irrigation: Causes drought stress, tip burn.
• Solution: Maintain optimal field moisture—avoid waterlogging or drying.

3. Sunburn / Heat Stress

• Intense sunlight and high temperatures can cause leaf tip bleaching.
• Common during transplant shock or when seedlings are suddenly exposed to strong sunlight.
• Solution: Provide partial shade to young seedlings or improve water management.

4. Chemical Injury / Fertilizer Burn

• High concentration of urea or foliar sprays can burn leaf tips.
• Tip burn appears white or pale brown.
• Solution: Dilute chemicals properly; avoid spraying during peak heat.

5. Disease or Pest Damage (Less Common for White Tips)

• Leaf scald or blast can start as discoloration at tips, but usually turns brown, not white.
• Check for lesions or fungal growth to rule out

White tips in hydroponically grown rice seedlings are likely due to nutrient imbalance (especially zinc), pH issues, light burn, or water stress. Start by checking your nutrient mix and pH, then investigate light intensity and water quality.

Answer:

White tips on hydroponically grown rice seedlings are often due to zinc deficiency, nutrient imbalance, or pH issues affecting nutrient uptake. Light burn or salt stress can also be contributing factors.

Reference:

Yoshida, S. (1981). Fundamentals of Rice Crop Science. International Rice Research Institute (IRRI